KR100971898B1 - Estimating superannuation method of facilities - Google Patents

Abstract

The present invention relates to a method for evaluating deterioration of facilities in the petrochemical, oil refining, and power generation industries. A method of preparing a replica film by duplicating a microstructure of a facility to evaluate the degree of deterioration, and accessing a retrieval system through the Internet And selecting a parameter according to the steel grade of the facility and the use environment of the facility in the search system, and selecting a grade which is judged to be the most similar by comparing the replica film with the tissue photograph registered in the parameter. It provides a method for evaluating the deterioration of the facility, characterized in that the step of preparing a countermeasure according to the selected grade.

According to the present invention, it is possible to easily read the deterioration grades for the facilities in the petrochemical, oil refining, and power generation industries even at low cost, even for non-experts and non-experts related to the metal structure, so that the optimum replacement time for the target equipment can be determined. To prevent damages such as explosion, fire, etc., thereby minimizing the loss of life and property.

Petrochemical, refinery, power generation facilities, deterioration degree, evaluation

Description

Evaluation method of facility deterioration {ESTIMATING SUPERANNUATION METHOD OF FACILITIES}

The present invention evaluates the degree of deterioration of equipment mainly used in harsh atmospheres such as petrochemical and oil refining plants, power generation, and heating, and accurately predicts the remaining life of equipment and timely repairs and replacements. As a method for evaluating the degree of deterioration of a facility that can be prevented in advance, and more specifically, it relates to a method of evaluating the degree of deterioration of a facility so that even non-experts can easily assess the deterioration of the facility directly through the Internet.

In general, most of the facilities installed in petrochemical, oil refining plants, and power generation industries are exposed to corrosive environments such as hydrochloric acid and sulfuric acid, and are operated under severe conditions at high temperature and high pressure. It is undergoing various deterioration such as tissue change, creep, thermal stress, carburization, sulfidation, etc. Due to these deterioration factors, the damage rate of the equipment is faster than that of the equipment used under normal conditions. In addition, the domestic industry is a aging device, and accidents occur frequently.

Therefore, in the art, it is necessary to analyze the deterioration factors of the material to evaluate the remaining life of the facility, and to prepare a countermeasure accordingly, to increase the service life of the facility and to have many opportunities for maintenance inspections that can prevent large accidents such as explosions in advance. We have been conducting regular inspections as necessary.The technician working at the production site lacks the specialized knowledge to analyze the deterioration factors of the facility and cannot evaluate the degree of deterioration and the remaining life of the facility. The present situation is evaluating the province.

However, in case of requesting a specialized institution, it is difficult to carry out the evaluation work in a timely manner due to the complicated procedure required for requesting, and therefore, it is possible to shorten the repair and replacement time of parts, resulting in shortening the lifespan of the facility or causing a large accident. There is a problem that can be caused, and there is also a problem that the request cost is expensive.

The present invention was devised to solve such a problem, and even non-experts, ie, technicians in the production site, can easily access and evaluate themselves, and predict the time for repair and replacement of facilities by allowing them to perform tasks at low cost. The aim is to provide a way to prevent the occurrence of large-scale accidents as well as the life of the equipment.

The present invention to achieve the above object

Preparing a replica film by duplicating the microstructure of the equipment to evaluate the degree of deterioration;

Accessing the retrieval system through the Internet, selecting a parameter according to the steel grade of the facility and the use environment of the facility in the retrieval system, and comparing the replica film with the organizational pictures listed in the parameter. It provides a method for evaluating deterioration of the facility, characterized in that it comprises the step of selecting the grade to be judged, and preparing a countermeasure according to the selected grade.

In addition, the search system in the present invention is characterized in that a database that can search for organization photos classified by steel type, parameter, grade, etc. can be easily accessible to anyone on the Internet,

The steel is characterized in that the low carbon alloy steel, corrosion resistant steel, heat-resistant cast steel,

The parameter is characterized in that the degree of degradation, creep, stress corrosion cracking, fatigue fatigue cracking, carburizing, hydrogen damage, formulated according to the deterioration factors and use atmosphere, etc.

The grade is classified into degradation grades of A to F in consideration of the structure state of the carbides, cavity defects, fittings, hydrogen damage, and cracking degree, and indicates the extent of the remaining life of the equipment. Provide an evaluation method.

According to the present invention, it is possible to easily read the deterioration grades for the facilities in the petrochemical, oil refining, and power generation industries even at low cost, even for non-experts and non-experts related to the metal structure, so that the optimum replacement time for the target equipment can be determined. To prevent damages such as explosion, fire, etc., thereby minimizing the loss of life and property.

Hereinafter, the structure of this invention is demonstrated.

In the present invention, the user uses a replica film replicating the microstructure of the facility in order to evaluate the degree of aging of the facility, so that it can be compared with the data listed in the search system.

The retrieval system of the present invention allows anyone to easily access through the Internet, and the database is classified into various types of microstructured pictures collected by the inventors for decades in the field during the evaluation of deterioration of the facility by steel type, parameter, and grade. It is mounted on a computer.

Among the data installed in the retrieval system, the target steels are carbon steel, corrosion resistant steel, and heat resistant steel. It is classified as cast steel because these steels are representative steels mainly used in equipment. Of course, it is possible to classify into various steel grades as needed.

The parameters were categorized into carbide precipitation, carburization, creep, stress corrosion cracking, corrosion fatigue, and hydrogen damage, because of the change in microstructure, which is the main cause of deterioration among the various factors that cause the material of equipment to deteriorate. Due to deterioration and structural atmosphere (rapid tensile stress, impact, repeated tension, compressive stress, constant constant load, working stress, etc.) and environmental atmosphere (corrosion other than carbon and hydrogen penetration) to be.

Here, the precipitation of carbide refers to the transformation of microstructures or the precipitation of carbides in grain boundaries and mouth when metal materials such as carbon steel, corrosion resistant steel, and heat resistant steel are exposed to high temperatures for a long period of time. It is a representative deterioration factor that causes breakage.

Figure 1 shows the deterioration behavior of the microstructure of the low carbon low alloy steel, according to this deterioration of the microstructure can be seen that the damage caused by the working stress and environmental factors,

In Figure 2 it can be seen that according to the microstructure deterioration behavior of heat-resistant cast steel deterioration proceeds as the process carbide is spheroidized and coarsened,

3 shows that the process carbides exist in various forms in the austenitic base in the heat-resistant cast steel,

Figure 4 shows the severely deteriorated microstructure of the tube used for 20000 hours,

In FIG. 5, it can be seen that according to the microstructure deterioration behavior of the corrosion-resistant (heat-resistant) steel, carbides are precipitated in the grain boundary and the mouth to deteriorate, so that the precipitation of carbides is a representative factor of metal deterioration.

At this time, carburization occurs on the metal surface of the equipment used in the high temperature range and deterioration of the material is promoted by the change of volume, coefficient of thermal expansion, thermal conductivity, etc. The reaction proceeds repeatedly by forming a coke layer, reducing the effective cross-sectional area of the tube, and increasing the tube temperature and increasing the carburization due to the adiabatic effect of the coke layer.

In addition, creep is mainly generated in a facility operating under high temperature and high pressure, and after a long time, a defect called a cavity occurs in the material, and the amount of such a cavity increases with time, thereby increasing micro-crack. ), And it has a great influence on the deterioration of metals that ultimately cause damage. In particular, creep is known to be proportional to the degree of deterioration and stress of the microstructure, as the creep damage of FIG. 6 is classified into five stages and the microstructure state from the initial stage to the final fracture is shown.

These stress corrosion cracks are a type of damage that occurs under certain stress and corrosive environmental conditions and can occur in all metal materials.

In addition, fatigue fatigue crack refers to a crack propagation through metal as a result of cyclic tensile stress acting in the atmosphere that corrodes metal, which occurs only at a certain threshold of cyclic stress, that is, above fatigue limit. In contrast to pure mechanical fatigue, corrosion fatigue occurs at very small stresses. In contrast to stress corrosion cracking (SCC), it occurs in almost all aqueous solutions, regardless of the specific combination of ions and metals, and is known as a form of damage that can occur without the concentration of corrosive substances.

In addition, hydrogen damage may cause cracking by hydrogen reacting with metal surfaces or alloying elements at high temperatures, or hydrogen remaining in the gas in a gaseous state when a thick portion of steel containing hydrogen is rapidly cooled to room temperature at high temperatures. This is a form of damage in which internal cracks are caused by the pressure of hydrogen gas.

In the present invention, grades (degradation grades) are classified into six levels A to F because the classification system is effective for evaluating degradation grades, and it is possible to further classify them as necessary.

Degradation grade criteria and countermeasures classified in the present invention are as follows.

Degradation grade

condition
Remaining life
Countermeasures
A

Early stage

100%
4 years later
B

Progress Steps Between A and C
80%
Recheck after 2 years
C

Intermediate stage

60%
Periodic inspection
D
Progress Steps Between C and E
40% -Detailed review during cycle check
-Life diagnosis through sampling test
E

Terminal stage
20% -Recheck within 1 year
Determine when to repair or replace
F

Destruction stage

0%
Immediate repair or replacement

The effect of this invention is demonstrated below.

First, prepare a replica film that shows the microstructure photograph of the material by duplicating the material of the equipment that the user wants to evaluate, and then access the search system of the Internet, select the steel grade and the parameter, and the grade for each parameter is displayed on the screen.

At this time, if you select a similar grade by determining which grade according to the condition of the equipment, the corresponding organizational picture appears, and accordingly, the user judges whether the grade is the same by comparing the state of the film and the organizational picture to determine the corresponding grade. Can be found.

Of course, it is natural to develop and use an automatic program that can automate the contrasting function.

In addition, the user who confirms the grade can establish a plan and perform a task according to the measures specified in the grade.

1 is a microstructure state diagram showing the microstructure degradation behavior of low carbon low alloy steel,

Figure 2 is a state diagram showing the microstructure deterioration behavior of the heat-resistant cast steel,

Figure 3 is a photograph showing that there are various forms of process carbides in the austenite base in the heat-resistant cast steel,

4 is a photograph showing the severely deteriorated microstructure of the tube used for 20,000 hours,

5 is a state diagram showing the microstructure deterioration behavior of the corrosion-resistant steel and heat-resistant cast steel,

6 is a five-stage classification table of creep cavities.

Claims (5)

Constructing a database by classifying various microstructured photographs collected by class, parameter, and grade, and connecting a search system for searching to the Internet and registering a database in the search system; Preparing a replica film by duplicating a tissue of a facility to be evaluated for deterioration; Accessing the search system via the Internet; Selecting steel grades and parameters of the facility in the search system; Selecting the grade which is judged to be the most similar to the structure of the replica film by comparing the replica film with the microstructured photographs corresponding to the steel grades and parameters of the facility selected by the search system, and preparing a countermeasure according to the selected grade; Consisting of steps; The steel grade is subdivided into low carbon low alloy steel, corrosion resistant steel, heat resistant cast steel, The parameter is subdivided into degree of degradation, degree of creep, stress corrosion cracking, corrosion fatigue cracking, carburizing, hydrogen damage, and formula according to the deterioration factor and the use environment. The grade is classified into a plurality of degradation grades according to the structure of the carbide, cavity defects, fittings, hydrogen damage, cracking degree, indicating how long the remaining life of the equipment. delete delete delete delete

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