Corrosion and Condition Management

Operational risks associated with oil, gas, power stations, and petrochemical plants commence from the date the production plants are built. The wear and tear due to corrosion and erosion begins during construction under the useful life of the production plants. For any manufactured equipment , serviceability and maintenance is the only key factor to ensure safe operation. This requires a routine program of managed maintenance. Statistics prove that a predictive maintenance process is the only key factor that is cost effective. This predictive method requires the asset maintenance team to get onstream information on the condition of the plant for them to take appropriate action.

With the advent of dedicated computing technology the majority of the information captured in the form of the data sets is held on the system from which intelligent reports are processed and some form of risk based inspection decisions are taken. Further, this information is globalized with the assistance of remote access. All this is very constructive. The validity of the information is as accurate as the measuring device and the inspection method mode and its reporting standards.

Worldwide several methods have emerged. Each of them deploying some form of NDT from which assessments are made. Where Ultrasonic, Eddy currents, Magnetic particles, and Acoustic Emission all generate point data on these details, Film Radiography and Digital Radiography generate a pictorial image of the region under examination.

Corrosion and Condition Monitoring

Corrosion and erosion are major concern for any plant owner, as they result in huge ecomonic and environmental losses, when they go undetected. Insulated pipes cause even a greater threat, as the damage due to corrosion gets masked by the insulation cover.

Profile/Tangential Radiography is one of the proven methods for inspecting Corrosion Under Insulation (CUI). This method makes use of high-energy radiation source, generally Ir192 or Co60, as the geometric setup accounts for greater thicknesses to be penetrated.

CIT offers Digital Radiography solutions for Corrosion & Condition Monitoring, which enable you to carry out radiography in the same manner as conventional film radiography, however, with reduced radiation dosage. The radiographic image is captured on Imaging Plates (IP) , from where the image is read in digital format, to be stored as a digital image in electronic archives with 50+ years of data life. The digital image can be viewed, modified, inspected and analysed for defects, material loss and wall thickness using CIT's Image viewing and Corrosion & Condition Monitoring software packages that offer electronic measuring tools with digital precision.

Corrosion or erosion of material due to chemical reactions also results in material loss, which eventually results in leakage and accidents that prove expensive and therefore, must be avoided. Regular condition monitoring eliminates this catastrophe, as appropriate action can be taken prior to major damage occurring. Another useful tool included in CIT/Corrosion & Condition Monitoring package is measuring wall thickness and material loss based on the relative density differences.A number of different methods are included to analyse and display wall thickness/material loss information.

Besides the above techniques, CIT's Digital Radiography Technology comes equipped with the following:

> Distance Measurement
> Line Profile
> Advanced Line Profile
> Risk Based Inspection (RBI)
> Color Mapping
> Report Generation

Pipeweld Radiography

Pipeweld Radiography

½" to 6" OD pipe welds can be inspected radiographically for petrochemical industry, oil & gas sector, and compressor stations. CIT's novel high definition digital computed radiograph technology replaces the traditional film radiography, chemical processes, dark rooms and physical archives. Reusable flexible digital computed phosphor imaging plates are used instead of films.

The DIPs are exposed to the radiographic source similar to the conventional film radiography. After
exposure the DIPs are scanned by an intelligent high performance reader and the radiograph image is displayed on the high brightness, high resolution monitor. The displayed radiographs are diagnostically interpreted for welds and electronic reports are generated, which are then permanently archived in the project, as plant process information.

The above technology is fast and efficient that enables the complete weld to be inspected within 2 to 4 minutes. Thus, over 150 pipe welds can be radiographed on a daily 12 hours shift. The radiograph contrast and image flow sensitivity matches the quality of the conventional radiograph film. Hence, the international radiographic acceptance standards are fully met. Further, the phosphor imaging has its own ASME V and European standards that are fully met.

In addition the technology meets the following directives:

> Directive 80/1107EEC establishes provision of a general nature and envisages individual directives on several hazardous materials (including ionising radiation of the type used in industrial radiography), whereby the principle of keeping workers exposure to these materials to ’as low reasonable achievable’ (ALARA).

> Directive 89/391/EEC: COM/2003/0127 final COD99/0085 covers aspects of safety at work and specifically highlights the risks to using industrial film radiography.

> In UK, the Ionising Radiation Regulation 1985 (IRR85) are based on the recommendations of the International Commission of Radiological Protection Publication ICRP26, and largely implement the Council Directive 80/836/Euratom (BSS80).