1、Application Background

With the development of economy, the number of pressure special equipment increases sharply, and its operation risk increases gradually. Among them, the pressure pipe with long life has corrosion, leakage and other safety risks, and its operation safety has become the top priority of special equipment safety production. Traditional nondestructive testing methods can only provide inspection and testing personnel and equipment management personnel with the current status of equipment defects, but cannot give the cause of pressure equipment defects. The analysis of the causes of equipment defects can provide reasons for defects for inspection and testing personnel and equipment users, provide good data support for later equipment maintenance and corrosion prevention, and help special equipment management units to reasonably and effectively monitor the origin and development of special equipment defects under pressure. At present, researchers in the world have applied X-ray diffractometer (XRD) technology to the inspection and testing of pressure special equipment and cause analysis, and obtained good application effect. For example, Ma Lei (2015) used X-ray diffractometer (XRD) to analyze the scale composition and cause of industrial boilers, and gave the technical basis for the later industrial boiler scale removal. In this paper, combined with the actual situation of the inspection and detection of pressure pipelines, the use of more efficient portable X-ray diffraction (pXRD) analyzer, qualitative and quantitative analysis of the corrosion layer of a chemical plant in Hubei industrial pipeline corrosion, through the analysis of the composition of the corrosion, infer the source of the material, give the possible causes of corrosion in the pressure pipeline. It provides a reference for further preventing corrosion in pressure pipelines from occurring again and later maintenance. At the same time, it can provide a new important clue for the investigation of pressure special equipment safety accident.

2、Scaling in Oil and Gas Assets

Scaling and corrosion can affect equipment throughout the oil and gas supply chain, from exploration and extraction to pipelines and refineries. Understanding the composition of scale and corrosion products can help the maintenance team immediately implement appropriate scale control measures or apply effective corrosion additives. For example, hydrochloric acid is commonly used to remove calcium carbonate scaling, while calcium sulfate scaling can be removed using chelating agents such as EDTA.

In the past, maintenance teams had to send samples to a lab far from the site for analysis, typically waiting days or weeks for results, or trying to process them using expensive chemical treatments that risked damaging the equipment. However, the amount of scaling and corrosion products commonly found in oil and gas assets is generally limited, and THE XRD analyzer is a popular choice for rapid and efficient detection of these products.

3、Mud Deposit

Silt deposits are commonly found in refineries and usually consist of:

Hydrocarbons (e.g., lubricants and oils)  

Liquids (e.g., water and oil)   

Non-hydrocarbon or inorganic (e.g., scaling and corrosion)

Using a XRD analyzer to understand the inorganic composition of the silt helps complete the removal process and prevent the recurrence of the silt. Dichloromethane can be used to separate the inorganic components (scaling and corrosion products) from the silt, allowing for a more detailed characterization of scaling and corrosion products (by means of decrystallization).

4、Principle of X-ray Dffractometer

X-ray diffractometer (XRD) is a kind of X-ray analysis instrument based on non-destructive detection. It qualitatively and quantitatively analyzes the main components of samples by studying the crystal structure of samples. It is widely used in medical, chemical, material, biological, geological and other research fields. Traditional X-ray diffractometer (XRD) mainly in the large laboratory XRD instrument is given priority to, mainly contains the design more complex goniometer, external accessory equipment such as water cooling system, its large size, large energy consumption, need professional characteristics in actual use of calibration on a regular basis with a lot of restrictions. In this case, the advantages of portable X-ray diffraction analyzer gradually emerged. It has the characteristics of convenient sample preparation, high efficiency and energy saving, no need for regular calibration and portability, and has been more and more applied to rapid detection in the field. In addition, the accuracy of quantitative analysis results has a good linear correlation with the accuracy of X-ray diffractometer (XRD) in traditional large laboratory, which has a high reference value.

5、Product introduction

SHINE is a portable XRD/XRF equipment developed and produced by LANScientific Co., Ltd. SHINE mobile XRD system is a high-performance fully enclosed battery operated closed ray portable XRD analyzer, which can provide the whole crystal phase ID information of the main and minor components or trace components of materials through a quick one-time XRF scan of magnesium to uranium elements The system's minimal sample preparation technology and unique sample bay enable rapid sample analysis in the field.

The analysis speed and data quality of SHINE are extremely high, and it provides users with quantitative chemical composition values in real time on the test site where users need to know the test results most.

The SHINE is shipped with the necessary software (CrystalX analysis software) for processing X-ray diffraction data results. This software integrates AMCSD ore database, ICDD ore database and ICSD ore database to support users to match objects across databases. For quantitative analysis, CrystalX analysis software provides a RIR quantitative analysis method and a tool for analyzing various diffraction patterns.

In addition, SHINE also provides XRD pattern data in a variety of file formats, making it easy for users to obtain XRD pattern interpretation information for third party projects.

6、Common Corrosion Products

Metal corrosion is more complex, usually including oxidation corrosion, sulfide corrosion, high temperature hydrogenation corrosion, sea water corrosion and electrochemical corrosion, due to the different environment of the metal in its corrosion mechanism is different, resulting in corrosion products are also different. Common corrosion products include such as iron oxide corrosion products are magnetite, goethite, water, iron ore, lepidocrocite, six-party lepidocrocite, sifang lepidocrocite, hematite, iron ore, the corrosion products mainly produces in carbon steel pipe, also found in oil and gas pipeline of barite, calcium carbonate, gypsum, calcite, lapis lazuli, etc. For urban water supply, it is common in quartz, albite, gypsum, chlorite, illite, microplagioclase, jarosite, iron and carbonate precipitation.

These are easily detected and analyzed by X-ray diffractometer (XRD). Scale, the earliest known corrosion product, builds up slowly in pipes and containers. Rust attached to a metal surface is also a type of corrosion. Analysis of corrosion and identification of species can determine the causes of corrosion, such as dissolved element mixing, temperature changes, PH changes, bacterial action, and oxidation. By understanding this information, we can find out the method of removing corrosive substances and the prevention plan.

7、Sampling and Sample Preparation

In this experiment, the SHINE portable X-ray diffraction (XRD) analyzer of LANScientific was used to detect and analyze the corrosion/scale layer in the pipe at the bottom of a water tank, and several samples of corrosion in the pipe at the bottom of the water tank were collected The corroded layer samples in the block pipes were dried for 2 hours in an oven of 120 degrees Celsius, and powder samples smaller than 100um were prepared by the pocket sample preparation box provided by LANScientific. The samples were put into the sample chamber for detection and diffraction patterns of the samples were obtained. The CrystalX analysis software was used to conduct qualitative and quantitative analysis of the diffraction patterns.

Sample preparation box

Corrosion Analysis Process

8、Equipment configuration

Instrument Model： SHINE

Anode：Co

Voltage： 30kV

Analysis time： 10mins

9、Analysis Result

Results of tests by LANScientific's SHINE portable X-ray diffraction (XRD) analyzer show that the main component of the corrosion/scale is magnesium calcite, indicating that the piping equipment is in frequent contact with mineral-containing water and minerals are accumulated in the equipment. In addition, the analysis results show that there is a certain amount of quartz, which may come from impurities attached to the medium in the pipeline. In summary, the analysis results reflect the fact that the corrosion samples were generated in a high mineral water environment, which confirms the basic situation of the experimental sampling site.

10、Conclusion

From the analysis results, the SHINE portable XRD analyzer of LANScientific can quickly analyze the corrosion and scale on the spot, so as to obtain the information of corrosion components in time, help to understand the causes of corrosion, and find a solution to prevent corrosion.