Petrochemical Refineries

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).

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 Condition Monitoring

Corrosion or erosion of material due to chemical reactions result in material loss. This material loss eventually results in leakage and accidents, which are expensive and thus must be avoided. Regular condition monitoring eliminates this catastrophe, as appropriate action can be taken prior to major damage occurring. A radiograph film or digital radiograph is taken of the effected area using conventional radiography or a digital filmless radiography system. The image information is used to assess the material loss by measuring the radiographic density that relates to the material loss.

Conventional film radiography based upon Iridium source radiography has been used in the field for the last 20 to 30 years. As a picture tells a thousand words hence, the radiographic imaging is extremely powerful, further added by the fact that one can look at internal composition of the material. However, there is a general reluctance towards it because of it pitfalls that include high radiation doseage, film processing, chemicals and dark rooms, contamination area, high exposure times, manual reporting and interpretation that takes several hours.

With the advent of digital technology, which is based upon flexible imaging plates, when used in conjunction with flexible radiation shielding has emerged as a boon eliminating the shortfalls of film radiography while providing higher accuracy, same image quality and automated reporting facilities. In addition to measuring density differences, a density based pictorial image is colour coded to provide an instantaneous interpretation of the region and enables areas of material loss to be assessed i.e. pits and material loss. These areas can be further analyzed to enable detailed investigations to be made.

CIT's Computed and Digital Radiography Technology stands as a serious and effective alternative for asset management in production plants.

CIT's unique Digital Filmless Radiography system captures ultra high-resolution images of large areas of interest, and displays them on 21" monitors with 0.089mm resolution. The Digital Radiography System can be used for inspection of products which replaces real time radiography. The system performance is 5 to 6 times better than real time radiography. Also, production throughput is significantly increased ,as the X-ray imaging sensor area can have many small castings on the same image capture. The X-ray images are displayed in 1.5 seconds up to 200 seconds. Additionally, electronic archive of these images eliminates the image degradation and provides secure method of data storage. If required hard copy films can be printed by CIT which match the conventional film methods.

The major commercial benefits are more accurate and fast assessment of corrosion attack over large areas that can significantly reduce costs and time spent in maintenance planning and deployment.

The technology uses following techniques to assess wear and tear due to erosion/corrosion:

> Profile/Tangential Radiography
> Penetrated wall material thickness/loss estimation
> Flaw Depth assessment/Stereoradiography

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

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