1、 Item No. 24203 NACE International Publication 3T199 (2013 Edition) This Technical Committee Report has been prepared by NACE International Task Group (TG) 390,* “Techniques for Monitoring CorrosionField Applications.” Techniques for Monitoring Corrosion and Related Parameters in Field Applications
2、September 2012, NACE International This NACE International technical committee report represents a consensus of those individual members who have reviewed this document, its scope, and provisions. Its acceptance does not in any respect preclude anyone from manufacturing, marketing, purchasing, or us
3、ing products, processes, or procedures not included in this report. Nothing contained in this NACE report is to be construed as granting any right, by implication or otherwise, to manufacture, sell, or use in connection with any method, apparatus, or product covered by Letters Patent, or as indemnif
4、ying or protecting anyone against liability for infringement of Letters Patent. This report should in no way be interpreted as a restriction on the use of better procedures or materials not discussed herein. Neither is this report intended to apply in all cases relating to the subject. Unpredictable
5、 circumstances may negate the usefulness of this report in specific instances. NACE assumes no responsibility for the interpretation or use of this report by other parties. Users of this NACE report are responsible for reviewing appropriate health, safety, environmental, and regulatory documents and
6、 for determining their applicability in relation to this report prior to its use. This NACE report may not necessarily address all potential health and safety problems or environmental hazards associated with the use of materials, equipment, and/or operations detailed or referred to within this repo
7、rt. Users of this NACE report are also responsible for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate regulatory authorities if necessary, to achieve compliance with any existing applicable regulatory requirements prior to the use of
8、 this report. CAUTIONARY NOTICE: The user is cautioned to obtain the latest edition of this report. NACE reports are subject to periodic review, and may be revised or withdrawn at any time without prior notice. NACE reports are automatically withdrawn if more than 10 years old. Purchasers of NACE re
9、ports may receive current information on all NACE publications by contacting the NACE FirstService Department, 1440 South Creek Dr., Houston, Texas 77084-4906 (telephone +1 281-228-6200). Foreword Assessment of corrosion in the field is complex because of the wide variety of applications, process co
10、nditions, and fluid phases that exist in industrial plants where corrosion occurs. A wide range of direct and indirect measurement techniques is available, but each technique has its strengths and weaknesses. In some applications certain techniques cannot be used. Some techniques can be used online,
11、 while others are done off-line. Commonly more than one technique is used so the weaknesses of one are compensated for by the strengths of another. In other cases, a combination of different techniques can be synergistic, such as process sampling along with detection of corrosion upset. The purpose
12、of this technical committee report is to analyze the various techniques with respect to their benefits and limitations across the wide spectrum of industries in which they are used. One technique, such as pH measurement, has considerably different features depending on the industry and environment i
13、n which it is used. A wide spectrum of experienced field users have contributed to this report. This report is intended as a practical reference for both new and experienced users. For new users, it provides an understanding of the practical aspects of each technique. For experienced users, it can b
14、e helpful in assessing less commonly used techniques, or the implications of using a familiar technique in a totally different operating environment. NACE International 2 There are several ways in which the many techniques can be subdivided. In this report, the categories have been selected on the f
15、ollowing basis: Direct Techniques Intrusive Nonintrusive Indirect Techniques Online Off-Line Direct techniques are those that measure a parameter changed directly by corrosion or erosion. Indirect techniques are those that measure a parameter that either influences, or is influenced by corrosion or
16、erosion. The above categorization provides a good method of segregating the techniques for internal monitoring. Some of the techniques also are used for external monitoring of pipelines and buried structures in soil and concrete. This is covered more specifically in NACE Publication 05107, “Report o
17、n Corrosion Probes in Soil and Concrete.”1 In general, the techniques have been categorized by their most common usage. Intrusive techniques in internal monitoring are any of those that require access through the pipe or vessel wall for measurements to be made. Intrusive or nonintrusive is not a def
18、inition of whether the probe projects into the process flow or not. Most commonly, intrusive techniques make use of some form of probe or test specimen, and these techniques include flush probe designs. Indirect techniques can be either online or off-line. With online methods the measurement is made
19、 without removing the monitoring device from the process. With off-line methods, a sample or specimen is removed for analysis. During the preparation of the first edition of this report it was recognized that categorizing some techniques as inspection rather than monitoring was somewhat arbitrary. M
20、onitoring and inspection are essentially descriptions of opposite ends of the measurement frequency spectrum. Monitoring infers the recording of a parameter in real time or near real time, whereas inspection has a time lag between an event and the collection of the data about that event. Consequentl
21、y, inspection is a post-event analysis. Technological improvements have generally improved sensitivities in many techniques. The more sensitive techniques can detect corrosion-related changes as they occur and permit remedial actions to be taken before significant damage occurs. Such techniques are
22、suited to monitoring. The less sensitive techniques may not permit remedial measures to be taken before significant damage has occurred, and while suitable for inspection they may not be suitable for monitoring. While this report covers as many techniques as could be defined, many of them are not wi
23、dely used in the field for a variety of reasons involving complexity, cost, suitability for field use, their proprietary nature, field support, technical expertise of the operator, and their applicability to the wide range of plant applications. In general, the most common techniques currently used
24、are mass-loss coupons, electrical resistance (ER) probes, linear polarization resistance (LPR) probes, and ultrasonic testing (UT). Leak detection techniques have not been included because they are used as failure detection techniques rather than prevention detection techniques. This is not to say t
25、hey are not useful in their own right, only that they are not within the scope of this report. Pigging monitoring technology also has been specifically excluded; however, most of the measurement techniques used in these tools also are described in this report. In this revision of the report the foll
26、owing additions have been made: Long-range UT Fiber optic strain gauges High-resolution ER A new method of hydrogen probe monitoring Extended-analysis coupons During the 10 years since the first edition of this report, developments in electronics and software have significantly enhanced the sensitiv
27、ity, noise rejection, and general operational convenience of many of the techniques. In general, the main features of each technique have not changed significantly, but when such changes have occurred, they have been noted. NACE International 3 The following techniques were not included for the reas
28、ons stated below: Magnetic tomography monitors and analyzes from above ground changes in the magnetic field of buried pipelines caused by stress changes from defects. At the time of publication of this revision, sufficient field experience could not be obtained to properly review the technique. Acou
29、stic emission for assessment of general corrosion monitors the noise from spalling corrosion product. The method is considered a coarse screening tool before using other inspection techniques. At the time of publication of this revision, there was insufficient field experience feedback to properly r
30、eview the technique. Acoustic emission used for solids detection. This was generally considered beyond the scope of monitoring of corrosion and corrosion-related parameters, although it does relate to erosion that is cited in other parts of the report. This method will be analyzed and discussed for
31、possible inclusion in the next revision of the report. Online gas chromatography for gas analysis of process fluids is sometimes used to determine, for example, hydrogen sulfide content which may relate to corrosion control. At the time of publication of this document revision, there was insufficien
32、t information and field review of the technique to allow inclusion. This method will be analyzed and discussed for proposed inclusion in the next revision of the report. This NACE technical committee report was originally published in 1999 by Task Group (TG) T-3T-3, a component of Unit Committee T-3
33、T, “On-line Monitoring Technology.” It was revised in 2012 by TG 390, “Techniques for Monitoring Corrosion and Related Parameters in Field Applications,” which is administered by Specific Technology Group (STG) 62, “Corrosion Monitoring and MeasurementScience and Engineering Applications”; and spons
34、ored by STG 31, “Oil and Gas ProductionCorrosion and Scale Inhibition.” This NACE technical committee report is published under the auspices of STG 62. NACE technical committee reports are intended to convey technical information of state-of-the-art knowledge regarding corrosion. In many cases, they
35、 discuss specific applications of corrosion mitigation technology, whether considered successful or not. Statements used to convey this information are factual and are provided to the reader as input and guidance for consideration when applying this technology in the future. However, these statement
36、s are not intended to be requirements or recommendations for general application of this technology, and must not be construed as such. Figures 1, 2, and 3 provide an overview of this report, and illustrate the Paragraph numbers where each topic is discussed. _ *Chair Allan Perkins, Rohrback Cosasco
37、 Systems, Santa Fe Springs, CA. NACE International 4 Section 1: Report Overview and Flow Diagram Figure 2 Physical 3.1 Physical Techniques/Metal Loss 4.1 Physical Techniques/Crack Detection and Propagation 4.2 Mass-Loss Coupon 3.1.1 Extended-Analysis Coupon 3.1.2 Pit Initiation Analysis 3.1.2.1 Elec
38、trical Resistance 3.1.3 Visual Inspection 3.1.4 Intrusive Measurement Techniques 3.0 Nonintrusive Measurement Techniques 4.0 Direct Techniques Indirect Techniques Techniques for Monitoring Corrosion and Related Parameters in Field Applications DC Techniques 3.2.1 AC Techniques 3.2.2 Electrochemical
39、Noise 3.2.1.6 Linear Polarization Resistance 3.2.1.1 ZRA on Dissimilar ElectrodesGalvanic 3.2.1.2 ZRA on Single Electrode Array 3.2.1.3 Coupled Multielectrode Array 3.2.1.4 Potentiodynamic/ Galvanodynamic Polarization 3.2.1.5 Electrochemical Impedance Spectroscopy 3.2.2.1 Harmonic Distortion Analysi
40、s 3.2.2.2 Ultrasonic TestingThickness Measurement 4.1.1 Magnetic Flux Leakage 4.1.2 Electromagnetic Eddy Current Testing 4.1.3 Electromagnetic Remote Field Testing 4.1.4 Radiography Testing 4.1.5 Surface Activation and Gamma Radiometry 4.1.6 Electrical Field Mapping 4.1.7 Acoustic Emission 4.2.1 Ult
41、rasonic TestingFlaw Detection 4.2.2 Ultrasonic TestingFlaw Sizing 4.2.3 Guided Wave Testing 4.2.4 Figure 1: Direct Techniques Electrochemical 3.2 NACE International 5 Figure 2: Indirect Online Techniques Figure 3 Techniques for Monitoring Corrosion and Related Parameters in Field Applications Corros
42、ion Products 5.1 Electrochemical Techniques 5.2 Water Chemistry Parameters 5.3 Fluid Detection 5.4 Process Parameters 5.5 Deposit Monitoring 5.6 Hydrogen Monitoring 5.1.1 Corrosion Potential 5.2.1 pH 5.3.1 Flow Regime 5.4.1 Pressure 5.5.1 Fouling 5.6.1 Thermography 5.7.1 External Monitoring 5.7 Cond
43、uctivity 5.3.2 Dissolved Oxygen 5.3.3 Oxidation- Reduction Potential 5.3.4 Flow Velocity 5.4.2 Temperature 5.5.2 Dew Point 5.5.3 Strain Measurement Fiber Optic 5.7.2 Figure 1 Direct Techniques Indirect Techniques Indirect Online Measurement Techniques 5.0 Off-Line Measurement Techniques 6.0 NACE Int
44、ernational 6 Figure 2 Direct Techniques Indirect Techniques Techniques for Monitoring Corrosion and Related Parameters in Field Applications Online Techniques 5.0 Indirect Off-Line Measurement Techniques 6.0 Water Chemistry 6.1 Residual Inhibitor 6.2 Chemical Analysis of Process Samples 6.3 Microbio
45、logical Analysis 6.4 Alkalinity 6.1.1 Metal Ion Analysis 6.1.2 Concentration of Dissolved Solids 6.1.3 Gas Analysis 6.1.4 Residual Oxidant 6.1.5 Filming Corrosion Inhibitor Residual 6.2.1 Reactant Corrosion Inhibitor Residual 6.2.2 Sulfur Content 6.3.1 Total Acid Number 6.3.2 Nitrogen Content 6.3.3
46、Salt Content of Crude Oil 6.3.4 Figure 3: Indirect Off-line Techniques NACE International 7 Section 2: Definition of Terms The definitions of many of the corrosion-related terms used in this report can be found in NACE/ASTM(1) G193. Other terms not included therein that have been used in this report
47、 are defined as follows: Direct Measurement: Measurement of parameters changed directly by corrosion or erosion. Indirect Measurement: Measurement of a parameter that influences, or is influenced by, corrosion or erosion. Inline Monitoring: Monitoring that uses equipment installed directly in the bu
48、lk fluid of the process, but data acquisition requires extraction of probes or process shutdown for analysis (for example, mass-loss coupons). Intrusive Monitoring: Monitoring that requires penetration through the pipe or vessel wall to gain access to the interior of the equipment. Nonintrusive Moni
49、toring: Monitoring from the outside of the pipe or vessel wall without having to gain access to the interior of the equipment. Online Monitoring: Monitoring that uses equipment installed for continuous measurement of metal loss, corrosion rate, or other parameters in an operating system. Data are obtained without removing the monitoring device. Off-Line Monitoring: Monitoring that uses methods in which a sample is taken for subsequent analysis. Real-Time Measurements: Measurements that can detect changes in the parameter un
