New Developments in Measuring Low Silicon in Process Piping Using Handheld X-ray Fluorescence (XRF)

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2 New Developments in Measuring Low Silicon in Process Piping Using Handheld X-ray Fluorescence (XRF) Presented by: Mark Lessard Business Development Manager Thermo Fisher Scientific

3 Outline Introduction- Corrosion Failures in Oil and Gas Sulfidation / Sulfidic Corrosion Elemental Analysis and Positive Material Identification (PMI) Principals of XRF Advances in handheld XRF PMI tools for Sample Preparation Interactive Demonstration of XRF Questions and Answers

4 Corrosion Failures in Process Piping 41% of the largest losses in the hydrocarbon processing industry resulted from failures in piping systems Corrosion is one of the leading causes of piping failures OSHA s National Emphasis Program (NEP) includes positive material identification (PMI) Recognized And Generally Accepted Engineering Practices or RAGAGEP Example RAGAGEP for PMI: API RP 578, Material Verification Program for New and Existing Alloy Piping Systems, Section 4.3 CSB, Safety Bulletin Positive Material Verification: Prevent Errors During Alloy Steel Systems Maintenance, BP Texas City, TX Refinery Fire Second International Symposium on the Mechanical Integrity of Process Piping January 1996, Houston, TX, USA

5 Sulfidation/Sulfidic Corrosion Two mechanisms: Hydrogen-free sulfidation H 2 /H 2 S Corrosion Result of naturally occurring sulfur compounds found in crude oil Causes accelerated corrosion in steel fittings, piping, heater tubes, and pressure vessels when the oil is heated for separation A significant cause of leaks and failures of piping systems within the refining industry

6 Sulfidation/Sulfidic Corrosion The rate of sulfidation corrosion is a function of many factors including Temperature Total sulfur concentration in the oil Types of sulfur compounds present Type of stream (light gas or heavy oil) Velocity Heat transfer conditions The presence or absence of hydrogen The material of construction

7 Using Elemental Analysis to Prevent Hydrogen Free Sulfidation Sulfidation Corrosion Increasing chromium content has a substantial effect of lowering the rate of sulfidation When carbon steel components are exposed to hydrogen-free sulfidation, those components with low Si content (<0.10%) may corrode at a significantly higher rate ( API 939-C ) H 2 /H 2 S Corrosion Carbon and low-alloy steels are ineffective in combating sulfidation below alloying levels of 12Cr-1Mo It is most common to use 18Cr-8Ni (300-series stainless) or higher alloyed steels in these environments

8 In-Situ Elemental Analysis of Piping Systems 2 Primary Technologies for Portable Analysis: Optical Emission Spectroscopy (OES) Technique of vaporizing sample surface and analyzing the emitted light spectra. The wavelength of the light corresponds to the elements present, while the intensity is a function of quantity of that element. X-ray Fluorescence Spectroscopy (XRF) Technique of exciting and ejecting atoms inner shell electrons with x-ray radiation and analyzing the fluorescent x-rays emitted when the atoms return to a stable state. X-ray energies emitted correspond to the individual elements, while the intensity is a function of quantity.

9 Pros: Accurate Handheld XRF Spectroscopy Portable - The handheld XRF analyzer weighs approximately 1.3 kg (3 lbs.) and is transported in a belt holster at the user s side Reduced sample preparation Completely nondestructive Simplicity - XRF technology is user-friendly, allowing relatively unskilled operators to participate in the inspection process Cons: Can measure elements only down to Mg on the periodic table (cannot do carbon) Stricter regulation and licensing requirements

10 How XRF Works Each individual element produces its own set of characteristic x-rays; the basis for qualitative analysis By counting the number of characteristic x-rays of a given element we can determine its concentration; the basis for quantitative analysis

11 XRF Evolution in Performance Since late 1960s, XRF has evolved through 7 generations; each generation has added new measurement capabilities as indicated by the (3) groups below Smaller, Faster, Better performance & Easier to use Today, nearly all alloys can be tested with these powerful tools. This addresses PMI Concerns in the Upstream /Downstream & Transportation Markets Measured (1) Element at a time to: >= 1.00% Chemistry in >/= 1 to 2 minutes Measured ( 16 to18 ) Elements at a time to: >= 0.01% Chemistry in </= 30 to 60 seconds Measures ( 25 to 30 ) Elements at a time to: >/= 0.003% Chemistry </= 3 to 12 seconds

12 New Ultra Detector Technology The Specs 25mm 2 to 45mm 2 Silicon Drift Detector (SDD) Greater surface area allows for maximization of tube current and greater overall light element X-Ray flux. Optimized voltage- By reducing voltage (with larger detector) it allows for excitation of Si without measuring Fe for improved Limits of Detection ( LOD ) Thinner window to maximize Mg-Si detection of returning fluorescence X-Ray energy Higher count rate of crucial light elements ( 400K counts per second ) The Results Next evolution in light element analysis in air (Mg, Al, Si, P, S) Detection limit for Silicon approximately 350 ppm in air. Increased sensitivity for tramp & trace elements in all alloys Even FASTER analysis of alloy and metals testing New Technology Old Technology

13 Auto Filters for Different Groups of Elements

14 Elements of Interest: Limits of Detection (LOD) Si Mn Ni Cu Cr Mo Detection Limits Limits of detection for advanced handheld XRF analyzers in ppm (mg/kg) SDD detector, 60 seconds per filter without He purge Main Filter is for: All Elements Low Filter for: Cr, V, Ti Light Filter is For: S, P, Si, Al, Mg

15 Existing Piping Systems ( Retro-Active PMI ) Programs Priority for API RP nd Edition High Temperature Sulfidic Corrosion - API RP 939-C Process Units Susceptible to Sulfidation: Carbon Steels with low silicon (0.10%) content can corrode at an accelerated rate Assets at risk from this type of degradation should apply PMI control to determine Silicon levels. (Retro-Active PMI is suggested and to follow API 578.) See API 571 and API RP 939-C See Section & 5 Sample Preparation is Required Low Si-33%,PMI-18%,Specification Break-17%

16 Corrosion Rate of Low-Si Carbon Steel

17 Measuring Low Silicon in the Field Current Technologies both ( XRF/OES) have limits for the Process Temperature Range. Proper Sample preparation is required. Most material of concern for Sulfidation is Carbon Steel piping installed before This material was usually double/tripled stamped ( A53/A106/API 5LB,& A285 Plates ). Typically, fittings have higher Si content, whereas piping straight runs have less Si. Specification breaks are also a contributing factor ( 5Cr welded to 9Cr ). Other Concerns for high temperature process ( 650 F and greater ) is using 5 Cr and 9Cr with both low Cr & Si.

18 Sample Preparation for Low Si Typical metal alloys used in the petrochemical industry will oxidize when exposed to atmospheric conditions. This oxide coating can affect the accuracy of the reading when performing an XRF analysis and must be removed. Sample contamination can occur if you prepare with the wrong abrasive disc. It is recommended to use grinding discs made from zirconium aluminum oxide. Zirconium is a metal not commonly found in steel alloys, so trace amounts found on the surface will not negatively affect test results. As a recommended starting point, the following grit sizes are suggested: Stainless Steel 120 grit Cr/Mo Steel 80 grit Carbon & Low Alloy Steel 60 grit. Rubber backing wheel Abrasive discs Handheld, right angle grinder