CN108918665B - Detection method for nitrate stress corrosion cracking - Google Patents
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Abstract
The invention belongs to the technical field of catalytic cracking devices, and particularly relates to a detection method for nitrate stress corrosion cracking, which is used for regeneration system equipment of a catalytic cracking device and comprises the following steps: s1, acquiring data of a regeneration system of the catalytic cracking unit; s2, determining whether the regeneration system of the catalytic cracking unit needs nondestructive testing for the nitrate stress corrosion cracking according to the obtained data, if so, turning to S3, and if not, stopping the testing; and S3, determining whether the regeneration system of the catalytic cracking unit has nitrate stress corrosion cracking or not according to the result of the nondestructive test in S8. The invention has the beneficial effects that: the invention comprehensively considers the influence factors of the catalytic cracking unit regeneration system nitrate stress corrosion cracking and comprehensively considers the influence generated by the factors to determine the UT scanning proportion.
Description
Technical Field
The invention belongs to the technical field of catalytic cracking devices, and particularly relates to a method for detecting stress corrosion cracking of nitrate.
Background
The catalytic cracking unit is one of the important production units of the petrochemical plant, and the catalyst regeneration system is one of the key process parts of the catalytic cracking unit and mainly used for realizing the regeneration and the reutilization of the catalyst. In recent years, corrosion cracking accidents have occurred in some domestic refinery regeneration system equipment, and the cause of cracks is analyzed to be stress corrosion cracking caused by nitrate. The risk-based inspection technology (API581) is introduced into China for the first time in 2003, the development of the risk-based inspection technology is helpful for equipment management, inspection strategies are optimized, and inspection time and maintenance cost are saved for enterprises. At present, most corrosion mechanisms of the oil refinery are almost covered in the API581 and judgment and calculation methods are given, but some more common corrosion mechanisms are not included in the API581 for some objective reasons, which brings certain difficulties to the work of domestic risk evaluation. Therefore, in order to facilitate the development of risk-based inspection work in China, it is necessary to provide a method for determining the corrosion mechanism that has not been incorporated in the API 581. Nitrate stress corrosion cracking is a common corrosion mechanism of a regeneration system of a catalytic cracking unit, the generation condition and the generation possibility of the nitrate stress corrosion cracking are required to be given, and meanwhile, because the regeneration system is large in equipment size and is difficult to perform nondestructive testing, the ultrasonic testing proportion aiming at the nitrate stress corrosion cracking can be given according to the possibility of the cracking.
Disclosure of Invention
In order to solve the problems, the invention provides a method for rapidly judging the possibility of the occurrence of the nitrate stress corrosion cracking of a catalytic cracking unit, and provides a detection method aiming at the nitrate stress corrosion cracking according to the possibility of the occurrence of the cracking.
The invention provides the following technical scheme:
a detection method of nitrate stress corrosion cracking is used for a regeneration system of a catalytic cracking unit, and comprises the following steps:
s1, acquiring historical operation data of a regeneration system of the catalytic cracking unit, acquiring material data of regeneration system equipment of the catalytic cracking unit, acquiring heat treatment data of the regeneration system equipment of the catalytic cracking unit, acquiring wall temperature data of the regeneration system of the catalytic cracking unit, acquiring material carbon content data of the regeneration system equipment of the catalytic cracking unit, acquiring pH value data of a flue gas condensate of the regeneration system of the catalytic cracking unit, and acquiring flue gas oxygen content data of the regeneration system of the catalytic cracking unit;
s2, determining whether the regeneration system of the catalytic cracking unit needs nondestructive testing for the nitrate stress corrosion cracking according to the obtained data, if so, turning to S3, and if not, stopping the testing;
and S3, determining whether the regeneration system of the catalytic cracking unit has nitrate stress corrosion cracking or not according to the result of the nondestructive test in S2.
Preferably, the historical operating data in S1 indicates whether the catalytic cracking unit regeneration system has a nitrate stress corrosion cracking phenomenon, wherein the nitrate stress corrosion cracking phenomenon is not generated and is CNThe stress corrosion cracking phenomenon of the generated peroxynitrate is CY；
The material data of the regeneration system equipment of the catalytic cracking unit in the step S1, wherein the regeneration system equipment of the catalytic cracking unit is made of carbon steel or low alloy steel material MCarbon steel or low alloy steelThe material of non-carbon steel or non-low alloy steel is MNon-carbon steel or non-low alloy steel；
The heat treatment data of the regeneration system equipment of the catalytic cracking unit in the S1 is ST, wherein the stress data of the regeneration system of the catalytic cracking unit subjected to the overheating treatment is STYData not subjected to the heat treatment is STN；
Wall temperature data of the catalytic cracking unit regeneration system in the S1 operation process, wherein the wall temperature of the catalytic cracking unit regeneration system is lower than the dew point temperature by TBelow dew point temperatureEqual to or above the dew point temperature of TDew point temperature and above；
The data of the carbon content of the material of the regeneration system equipment of the catalytic cracking unit in S1, wherein the material of the regeneration system of the catalytic cracking unitThe carbon content of the material is CC between 0.001 percent and 0.2 percentThe carbon content of the material is 0.001％-0Between 2% andthe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percent, and the material is CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percent；
And in the S1, the pH value of the flue gas condensate of the regeneration system of the catalytic cracking unit is V, wherein the pH value of the flue gas condensate of the regeneration system of the catalytic cracking unit is less than 7pH <7The pH value of the flue gas condensate is more than or equal to 7 and is VpH ≥7；
And in S1, the flue gas medium oxygen content data of the regeneration system of the catalytic cracking unit, wherein the medium oxygen content of the regeneration system of the catalytic cracking unit is OC which is less than 1.3 percentOxygen (V)<1.3％The content of oxygen in the medium is more than or equal to 1.3 percent and less than or equal to 1.8 percent is OC1.3 percent to 1.8 percent of oxygen (V)The medium contains oxygen content of more than 1.8 percent of OCOxygen (V) > 1.8%。
Preferably, in S2, the determining whether the catalytic cracking unit regeneration system needs to perform nondestructive testing on the nitrate stress corrosion cracking according to the obtained data specifically includes:
S＝f(a1，a2，a3，a4，a5，a6，a7)
wherein S represents whether nondestructive testing is required, and the value range is { S }Is that，SWhether or not}；
a1 indicates whether the nitrate stress corrosion cracking phenomenon has occurred, and its value range is { C }Y，CN}；
a2 represents a material factor having a value in the range of { M }Carbon steel or low alloy steel，MNon-carbon steel or non-low alloy steel}；
a3 represents a heat treatment factor, and its value range is { ST }Y，STN}；
a4 represents the wall temperature, which has a value in the range of { T }Below dew point temperature，TDew point temperature and above}；
a5 represents the carbon content of the material, and its value is in the range of { CCThe carbon content of the material is between 0.001 and 0.2 percent，CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percent}；
The pH value of the a6 flue gas condensate is in the range of { V }pH <7，VpH ≥7}；
a7 represents the media oxygen content, which ranges from { OCOxygen (V)<1.3％，OC1.3 percent to 1.8 percent of oxygen (V),OCOxygen (V) > 1.8%}；
According to the influence degree of the parameters on the nitrate stress corrosion cracking sensitivity and the result of the resultant force action, whether nondestructive testing on the nitrate stress corrosion cracking is required or not can be judged according to the following method:
when a2 is equal to MNon-carbon steel or non-low alloy steelWhen S is equal to SWhether or not；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STYWhen S is equal to SWhether or not；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TDew point temperature and aboveWhen S is equal to SWhether or not；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CYWhen S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2％When S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH ≥7When S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is 0.001% -0.2%，a6＝VpH <7，a7＝OCOxygen (V) >1.8％When S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH <7，a7＝OCOxygen (V)<1.3％When S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH <7，a7＝OC1.3 percent to 1.8 percent of oxygen (V)When S is equal to SIs that。
Preferably, when S ═ SIs thatI.e. non-destructive testing is required, non-destructive testing is performed by UT scanning, wherein the proportion of UT scanning is determined in the following way,
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CYWhen the ratio of UT scanning is not lower than 90%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2％When the ratio of UT scanning is not lower than 20%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH ≥7When the ratio of UT scanning is not lower than 20%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent，a6＝VpH <7，a7＝OCOxygen (V) >1.8％When the ratio of UT scanning is not lower than 90%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TDew pointBelow temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH <7，a7＝OCOxygen (V)<1.3％When the ratio of UT scanning is not lower than 20%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH <7，a7＝OC1.3 percent to 1.8 percent of oxygen (V)And in the meantime, the ratio of UT scanning is not lower than 90%.
The invention has the beneficial effects that: the invention comprehensively considers the influence factors of the nitrate stress corrosion cracking of the regeneration system of the catalytic cracking unit, including whether the nitrate stress corrosion cracking, the material factors, the stress factors, the wall temperature, the carbon content, the pH value and the oxygen content occur in the operation and inspection processes, and comprehensively considers the influence generated by the factors to determine the UT scanning proportion, thereby being capable of quickly and effectively detecting whether the nitrate stress corrosion cracking phenomenon occurs in the regeneration system of the catalytic cracking unit.
Drawings
FIG. 1 is a flow chart of the nitrate stress corrosion cracking detection method of the regeneration system of the catalytic cracking unit.
Detailed Description
The present invention will be described in detail with reference to the following examples.
1. Whether nitrate stress corrosion cracking occurs in the operation and inspection process; 2. material factors; 3. A stress factor; 4. wall temperature; 5. the carbon content; 6. the pH value; 7. oxygen content.
A detection method of nitrate stress corrosion cracking is used for a regeneration system of a catalytic cracking unit, and comprises the following steps:
s1, acquiring historical operation data of a regeneration system of the catalytic cracking unit, acquiring material data of regeneration system equipment of the catalytic cracking unit, acquiring heat treatment data of the regeneration system equipment of the catalytic cracking unit, acquiring wall temperature data of the regeneration system of the catalytic cracking unit, acquiring material carbon content data of the regeneration system equipment of the catalytic cracking unit, acquiring pH value data of a flue gas condensate of the regeneration system of the catalytic cracking unit, and acquiring flue gas oxygen content data of the regeneration system of the catalytic cracking unit;
s2, determining whether the regeneration system of the catalytic cracking unit needs nondestructive testing for the nitrate stress corrosion cracking according to the obtained data, if so, turning to S3, and if not, stopping the testing;
and S3, determining whether the regeneration system of the catalytic cracking unit has nitrate stress corrosion cracking or not according to the result of the nondestructive test in S2.
In a preferred embodiment, the historical operating data of S1 indicates whether the catalytic cracker regeneration system has undergone a nitrate stress corrosion cracking event, wherein the failure to undergo a nitrate stress corrosion cracking event is CNThe stress corrosion cracking phenomenon of the generated peroxynitrate is CY；
The material data of the regeneration system equipment of the catalytic cracking unit in the step S1, wherein the regeneration system equipment of the catalytic cracking unit is made of carbon steel or low alloy steel material MCarbon steel or low alloy steelThe material of non-carbon steel or non-low alloy steel is MNon-carbon steel or non-low alloy steel；
The heat treatment data of the regeneration system equipment of the catalytic cracking unit in the S1 is ST, wherein the stress data of the regeneration system of the catalytic cracking unit subjected to the overheating treatment is STYData not subjected to the heat treatment is STN；
Wall temperature data of the catalytic cracking unit regeneration system in the S1 operation process, wherein the wall temperature of the catalytic cracking unit regeneration system is lower than the dew point temperature by TBelow dew point temperatureEqual to or above the dew point temperature of TDew point temperature and above；
The data of the carbon content of the material of the regeneration system equipment of the catalytic cracking unit in the S1, wherein the carbon content of the material of the regeneration system of the catalytic cracking unit is CC between 0.001% and 0.2%The carbon content of the material is between 0.001 and 0.2 percentThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to0.2% of the total amount is CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percent；
And in the S1, the pH value of the flue gas condensate of the regeneration system of the catalytic cracking unit is V, wherein the pH value of the flue gas condensate of the regeneration system of the catalytic cracking unit is less than 7pH <7The pH value of the flue gas condensate is more than or equal to 7 and is VpH ≥7；
And in S1, the flue gas medium oxygen content data of the regeneration system of the catalytic cracking unit, wherein the medium oxygen content of the regeneration system of the catalytic cracking unit is OC which is less than 1.3 percentOxygen (V)<1.3％The content of oxygen in the medium is more than or equal to 1.3 percent and less than or equal to 1.8 percent is OC1.3 percent to 1.8 percent of oxygen (V)The medium contains oxygen content of more than 1.8 percent of OCOxygen (V) > 1.8%。
In a preferred embodiment, the step S2 of determining whether the regeneration system of the catalytic cracking unit needs to perform the nondestructive testing on the nitrate stress corrosion cracking according to the obtained data specifically includes:
S＝f(a1，a2，a3，a4，a5，a6，a7)
wherein S represents whether nondestructive testing is required, and the value range is { S }Is that，SWhether or not}；
a1 indicates whether the nitrate stress corrosion cracking phenomenon has occurred, and its value range is { C }Y，CN}；
a2 represents a material factor having a value in the range of { M }Carbon steel or low alloy steel，MNon-carbon steel or non-low alloy steel}；
a3 represents a heat treatment factor, and its value range is { ST }Y，STN}；
a4 represents the wall temperature, which has a value in the range of { T }Below dew point temperature，TDew point temperature and above}；
a5 represents the carbon content of the material, and its value is in the range of { CCThe carbon content of the material is between 0.001 and 0.2 percent，CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percent}；
The pH value of the a6 flue gas condensate is in the range of { V }pH <7，VpH ≥7}；
a7 represents the media oxygen content, which ranges from { OCOxygen (V)<1.3％，OC1.3 percent to 1.8 percent of oxygen (V),OCOxygen (V) > 1.8%}；
According to the influence degree of the parameters on the nitrate stress corrosion cracking sensitivity and the result of the resultant force action, whether nondestructive testing on the nitrate stress corrosion cracking is required or not can be judged according to the following method:
when a2 is equal to MNon-carbon steel or non-low alloy steelWhen S is equal to SWhether or not；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STYWhen S is equal to SWhether or not；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TDew point temperature and aboveWhen S is equal to SWhether or not；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CYWhen S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percentWhen S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH ≥7When S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH <7，a7＝OCOxygen (V) > 1.8%When S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe material containsThe carbon content is between 0.001 and 0.2 percent， a6＝VpH <7，a7＝OCOxygen (V)<1.3％When S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH <7，a7＝OC1.3 percent to 1.8 percent of oxygen (V)When S is equal to SIs that。
In a preferred embodiment, when S ═ SIs thatI.e. non-destructive testing is required, non-destructive testing is performed by UT scanning, wherein the proportion of UT scanning is determined in the following way,
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CYWhen the ratio of UT scanning is not lower than 90%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percentWhen the ratio of UT scanning is not lower than 20%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH ≥7When the ratio of UT scanning is not lower than 20%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH <7，a7＝OCOxygen (V) > 1.8%When the ratio of UT scanning is not lower than 90%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH <7，a7＝OCOxygen (V)<1.3％When the ratio of UT scanning is not lower than 20%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent， a6＝VpH <7，a7＝OC1.3 percent to 1.8 percent of oxygen (V)And in the meantime, the ratio of UT scanning is not lower than 90%.
In a particular embodiment of the present invention,
a certain catalytic unit of the medium petrochemical industry is connected to a smoke gas pipeline at the inlet of a smoke machine from a three-stage cyclone separator, and the smoke gas pipeline is not subjected to over stress corrosion cracking in the previous operation process, wherein a1 is CNThe material 1Cr18Ni9Ti, a2 ═ MNon-carbon steel or non-low alloy steelNo heat treatment after welding, a3 ═ STNThe smoke temperature is about 700 ℃, the dew point temperature is about 138 ℃, and a4 is TDew point temperature and aboveThe carbon content of the material is 0.07 percent, and a5 ═ CCThe carbon content of the material is between 0.001 and 0.2 percent，a6＝VpH <7Oxygen content a7 ═ OCOxygen (V) > 1.8%Since it is judged by the above method that nitrate stress corrosion cracking does not occur under these conditions, S ═ SWhether or notNondestructive testing for nitrate stress corrosion cracking may not be performed. No nitrate stress corrosion cracking corrosion mechanism is found in nondestructive testing in a plurality of overhaul.
The regenerator of heavy oil catalytic unit in a certain oil refinery has no cracking, and a1 ═ CNThe regenerator substrate is 16MnR, a2 ═ MCarbon steel or low alloy steelA3 taking STNThat is, the regenerator is not subjected to the whole heat treatment or the heat treatment effect is not good, the wall temperature is about 110 ℃, and the dew point temperature is 127 ℃ by analysis and calculation, so that a4 is TBelow dew point temperatureThe carbon content of the material is 0.18 percent, and a5 ═ CCThe carbon content of the material is between 0.001 and 0.2 percentpH 3.8, a6 ═ VpH <7The oxygen content in the flue gas is 1.96 percent (V), and the possibility of the equipment generating nitrate stress corrosion cracking is very high according to the judgment of the method, and the UT scanning proportion aiming at the nitrate stress corrosion cracking is recommended to be more than 90 percent. 2017 paired clothesAnd (4) carrying out maintenance, completely removing the lining below the transition section of the regenerator, carrying out 100% nondestructive testing on the welding seam, and finding a large number of cracks and penetrating individual cracks.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (2)
1. A detection method of nitrate stress corrosion cracking is used for a regeneration system of a catalytic cracking unit, and is characterized by comprising the following steps:
s1, acquiring historical operation data of a regeneration system of the catalytic cracking unit, acquiring material data of regeneration system equipment of the catalytic cracking unit, acquiring heat treatment data of the regeneration system equipment of the catalytic cracking unit, acquiring wall temperature data of the regeneration system of the catalytic cracking unit, acquiring material carbon content data of the regeneration system equipment of the catalytic cracking unit, acquiring pH value data of a flue gas condensate of the regeneration system of the catalytic cracking unit, and acquiring flue gas oxygen content data of the regeneration system of the catalytic cracking unit;
s2, determining whether the regeneration system of the catalytic cracking unit needs nondestructive testing for the nitrate stress corrosion cracking according to the obtained data, if so, turning to S3, and if not, stopping the testing;
s3, determining whether the regeneration system of the catalytic cracking unit has nitrate stress corrosion cracking or not according to the result of the nondestructive test in S2;
the historical operation data in the S1 shows whether the catalytic cracking unit regeneration system generates the nitrate stress corrosion cracking phenomenon, wherein the nitrate stress corrosion cracking phenomenon which does not occur is CNThe stress corrosion cracking phenomenon of the generated peroxynitrate is CY；
The material data of the regeneration system equipment of the catalytic cracking unit in the step S1, wherein the regeneration system equipment of the catalytic cracking unit is made of carbon steel or low alloy steel material MCarbon steel or low alloy steelThe material of non-carbon steel or non-low alloy steel is MNon-carbon steel or non-low alloy steel；
The heat treatment data of the regeneration system equipment of the catalytic cracking unit in the S1 is ST, wherein the stress data of the regeneration system of the catalytic cracking unit subjected to the overheating treatment is STYData not subjected to the heat treatment is STN；
Wall temperature data of the catalytic cracking unit regeneration system in the S1 operation process, wherein the wall temperature of the catalytic cracking unit regeneration system is lower than the dew point temperature by TBelow dew point temperatureEqual to or above the dew point temperature of TDew point temperature and above；
The data of the carbon content of the material of the regeneration system equipment of the catalytic cracking unit in the S1, wherein the carbon content of the material of the regeneration system of the catalytic cracking unit is CC between 0.001% and 0.2%The carbon content of the material is between 0.001 and 0.2 percentThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percent, and the material is CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percent；
And in the S1, the pH value of the flue gas condensate of the regeneration system of the catalytic cracking unit is V, wherein the pH value of the flue gas condensate of the regeneration system of the catalytic cracking unit is less than 7pH<7The pH value of the flue gas condensate is more than or equal to 7 and is VpH≥7；
And in S1, the flue gas medium oxygen content data of the regeneration system of the catalytic cracking unit, wherein the medium oxygen content of the regeneration system of the catalytic cracking unit is OC which is less than 1.3 percentOxygen (V)<1.3％The content of oxygen in the medium is more than or equal to 1.3 percent and less than or equal to 1.8 percent is OC1.3 percent to 1.8 percent of oxygen (V)The medium contains oxygen content of more than 1.8 percent of OCOxygen (V) > 1.8%；
In S2, determining whether the catalytic cracking unit regeneration system needs to perform nondestructive testing on nitrate stress corrosion cracking according to the obtained data specifically includes:
S＝f(a1，a2，a3，a4，a5，a6，a7)
wherein S represents whether nondestructive testing is required, and the value range is { S }Is that，SWhether or not}；
a1 indicates whether the nitrate stress corrosion cracking phenomenon has occurred, and its value range is { C }Y，CN}；
a2 represents a material factor having a value in the range of { M }Carbon steel or low alloy steel，MNon-carbon steel or non-low alloy steel}；
a3 represents a heat treatment factor, and its value range is { ST }Y，STN}；
a4 represents the wall temperature, which has a value in the range of { T }Below dew point temperature，TDew point temperature and above}；
a5 represents the carbon content of the material, and its value is in the range of { CCThe carbon content of the material is between 0.001 and 0.2 percent，CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percent}；
The pH value of the a6 flue gas condensate is in the range of { V }pH<7，VpH≥7}；
a7 represents the media oxygen content, which ranges from { OCOxygen (V)<1.3％，OC1.3 percent to 1.8 percent of oxygen (V),OCOxygen (V) > 1.8%}；
According to the influence degree of the parameters on the nitrate stress corrosion cracking sensitivity and the result of the resultant force action, whether nondestructive testing on the nitrate stress corrosion cracking is required or not can be judged according to the following method:
when a2 is equal to MNon-carbon steel or non-low alloy steelWhen S is equal to SWhether or not；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STYWhen S is equal to SWhether or not；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TDew point temperature and aboveWhen S is equal to SWhether or not；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CYWhen S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percentWhen S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent，a6＝VpH≥7When S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent，a6＝VpH<7，a7＝OCOxygen (V) > 1.8%When S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent，a6＝VpH<7，a7＝OCOxygen (V)<1.3％When S is equal to SIs that；
When a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent，a6＝VpH<7，a7＝OC1.3 percent to 1.8 percent of oxygen (V)When S is equal to SIs that。
2. The method of claim 1, wherein S is S ═ SIs thatI.e. non-destructive testing is required, non-destructive testing is performed by UT scanning, wherein the proportion of UT scanning is determined in the following way,
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CYWhen the ratio of UT scanning is not lower than 90%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is less than or equal to 0.001 percent or the carbon content is more than or equal to 0.2 percentWhen the ratio of UT scanning is not lower than 20%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent，a6＝VpH≥7When the ratio of UT scanning is not lower than 20%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent，a6＝VpH<7，a7＝OCOxygen (V) > 1.8%When the ratio of UT scanning is not lower than 90%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent，a6＝VpH<7，a7＝OCOxygen (V)<1.3％When the ratio of UT scanning is not lower than 20%;
when a2 is equal to MCarbon steel or low alloy steel，a3＝STN，a4＝TBelow dew point temperature，a1＝CN，a5＝CCThe carbon content of the material is between 0.001 and 0.2 percent，a6＝VpH<7，a7＝OC1.3 percent to 1.8 percent of oxygen (V)And in the meantime, the ratio of UT scanning is not lower than 90%.
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