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Analytical Instrumentation

Go to areas of Interest - Analytical Instrumentation Basics | Analyser Housings and Rooms | Analyzer Calibration | Analyser Calibration Gases | BTX and Total Aromatics | Chromatograph | Continuous Emission Monitoring | Density Analysis | Odorization Analysis | Oxygen Analysis | PH Analysis | Humidity Measurement | Oil in Water Analysis | Process Analyser Sample Systems | Specific Gravity | Spectrophotometer | Useful Analytical Instrumentation Books | Analyser Application

Analytical Instrumentation Basics

A new application guide entitled Liquid Analysis for Metals Extraction and Processing is available from Emerson Process Management. The guide outlines liquid analytical solutions for leaching and ore extraction, concentration and separation, finished product purification and waste disposal as well as approaches to network management for metals processing plants. The new guide literally walks the user through the major extraction and processing methodologies and techniques such as cyanide extraction, flotation, phase difference, steel treatment and much more.

Control Global have an excellent Process Analyser Systems page which provide an excellent Guide to several Process Analyzer Technology (PAT) System reference articles. These include;
- Process Analyzer Resources
- When is it Time to Retire your PAT System?
- PAT System Reliability
- What keeps Process Analyzer Engineers up at Night?
- Process Analyzer Reliability, Maintenance & Service
- Process Analyzer System Safety and Ergonomics Part II
- Process Analyzer System Safety and Ergonomics Part I
- More About Cost Estimating Process Analyzer Projects
- Cost Estimating for Process Analyzer Projects
- Project Roadmaps Get You There
- Accurately Scoping Process Analyzer Projects
- How to Launch an Analyzer System Lifecycle Reliability Program

On-Line Process Analyzers - Potential Uses and Applications – This document provides ideas for application of Precision Scientific process analyzers in petroleum refineries. The information is arranged by refining process. Included in this synopsis are applications which may be economically feasible in many refineries. The primary advantage to using on-line process analyzers in refining operations is the ability to control the product streams closer to specifications. Periodic analysis of the product streams leaving a particular unit can be used for both quality control and for control of the unit operation, in order to maximize the yield of high-value products. A dedicated process analyzer would be able to provide measurement results quicker and with better repeatability than laboratory analysis. This would allow for better control of heater loads, reflux, and the tracking of transients. Improved control would allow for greater yields of high value products by reducing the give-away needed to assure that all products meet specifications - from Expotechusa.

Analyser Housings and Rooms

How to Keep Analysers Cool in the Field - Anthony Leong and Martin Hess - Field-based process analysers are often sited in remote environments where they need protecting against harsh environmental conditions, and high daytime temperatures. For optimum performance and reliability, their electronics and sample conditioning systems must be maintained within prescribed temperature limits, requiring that the environmental protection shelter is well insulated and incorporates some form of cooling. Most analyser shelters currently use air conditioning (AC) systems to protect against high temperatures. These are expensive - especially if they need to be explosion-proof - and can account for a high percentage of the capital, energy and maintenance costs of a typical oil or gas analyser installation. Furthermore, they do not easily scale down to suit small shelters, and their performance decreases by as much as two thirds at high ambient temperatures. One recent trend is to employ passive cooling technology. Originally developed for pipeline instrumentation shelters in remote desert locations without an electricity supply, passive cooling systems (PCSs) have been deployed successfully over the past decade - from the excellent Pacetoday.  

Explosion Protection for Process Analysis - Safe operation up to the explosion limit - Jürgen Poidl and Helmut Schulz - Gas analysers are used for the continuous on line measurement of the composition of process flows in chemical production systems. These measurements provide support to key process functions of controlling and monitoring the temperature, humidity, and chemical composition of gases and liquids.  In some cases, commercial considerations and demands are resulting in the operation of production processes in chemical plants increasingly close to the explosion limit. It is therefore essential that the explosion- protected gas analysers used for monitoring the explosion limit continuously supply the necessary and reliable data to the process control systems. Using the special safety systems it is possible to operate gas analysers, the electrical equipment and the safety devices even when the process conditions are close to the limit - from Stahl.

International Standard IEC 61285 – Industrial Process Control Safety of Analyser Houses - Process analysers measure the characteristics of a process stream continuously and automatically. The process sample is introduced automatically and the system is designed for unattended operation and minimal maintenance. This document is designed to set forth minimum safety requirements for typical analyser houses (AHs). You will have to purchase this standard.  

Improving Analytics to Meet Process Industry Demands - Moving analyzers from the lab to a field-based shelter to the pipe will cut costs, reduce maintenance, and improve operations - Creating products from raw materials in pharmaceutical, petrochemical, and other process plants depends on intricate process systems executing numerous steps or unit operations. To ensure efficiency, quality, and safety, precise measurements must be taken during the various stages of production. These measurements have typically been made using instruments and analyzers. These devices supply information to plant personnel in control rooms and laboratories. Instruments are used to measure basic parameters, such as pressure, temperature, flow, and level. Sophisticated analyzers make more complex measurements concerning the composition of one or more components in a liquid or gas chemical stream. Both instrument and analyzer data are used as inputs to automation systems for the purpose of monitoring and controlling the process. Instrument technology has been used for decades and is highly refined, enabling these devices to be directly installed in pipes and vessels, delivering reliable readings with minimal maintenance.  Analyzers for some basic measurements have advanced to the level of instruments in terms of ease of use and reliability. In most cases, analyzers and related sample systems remain quite complex in terms of installation, maintenance, and operations – but recent advancements are changing this paradigm - from the ISA and InTech.

Analyzer Calibration 

Chemical Testing ISO/IEC 17025 Application Document - Annex H: Calibration of gas analysers - This document provides additional interpretative criteria and recommendations for the application of ISO/IEC 17025 in the field of Chemical Testing for both applicant and accredited facilities conducting calibration of gas analysers, except for motor vehicle emission testing to Australian design rules which is covered in Chemical Testing Annex I - from NATA.

Analyser Calibration Gases

Ensuring an Accurate Result in an Analytical Instrumentation System - Doug Nordstrom and Tony Waters - In many analytical instrumentation systems, the analyser does not provide an absolute measurement. Rather, it provides a relative response based on settings established during calibration, which is a critical process subject to significant error. To calibrate an analyser, a calibration fluid of known contents and quantities is passed through the analyser, producing measurements of component concentration. If these measurements are not consistent with the known quantities in the calibration fluid, the analyser is adjusted accordingly. Later, when process samples are analysed, the accuracy of the analyser’s reading will depend on the accuracy of the calibration process. It is therefore, imperative, that we understand how error or contamination can be introduced through calibration; when calibration can — and cannot — address a perceived performance issue with the analyser; how atmospheric pressure or temperature fluctuations can undo the work of calibration; and when and when not to calibrate - thanks to Swagelok and 

Thanks to Matheson Tri-Gas for the following
Calibration Standard Gases Are Key to Reliable Measurements -Ronald C Geib
Gas Data Book
Safe Handling of Compressed Gases
Conversion Tables
Materials Compatibility Guide
Threshold Limit Values
Lower and Upper Explosive Limits
Glossary of Terms

LPG, LNG and Other Liquid Hydrocarbon Standard Mixtures - Sometimes getting a standard sample can be hard this may be the answer - NPL can produce LPG (liquefied petroleum gas), LNG (liquefied natural gas) and other liquid hydrocarbon standards in two forms of vessel technology: constant pressure (piston) cylinders or dual-port valve dip-tube cylinders.

BTX and Total Aromatics

BTX and Total Aromatics by UV Absorbance -  Manufacturers are required to verify that household solvents do not contain aromatics above the hazardous carcinogenic levels. Hydrogenation processes in which an aromatic compound reacts with hydrogen over a metal catalyst are commonly used to purify solvents of trace amounts of aromatics. To maximize product yield, several parameters are optimized based on instantaneous indication of the total aromatics, a measurement that is also essential for verification of product purity - from Applied Analytics Inc.


HOKE Gyrolok® Chromatography Fittings - HOKE Gyrolok® tube fittings for use in gas or liquid chromatography applications and feature low dead volumes, male nut designs, as well as configurations utilising either press-fit or drop-in frits

50 years: Online Gas Chromatograph - Stephen M Bostic & Dr Jerry M Clemons - The most prolific and flexible online analytical measurement device for analysing discrete hydrocarbons in the hydrocarbon processing industry (HPI) is the process gas chromatograph (GC). It is estimated that there are more than 30,000 process gas chromatographs installed worldwide- This article takes a look at the past, present and a glimpse of the future of the online process gas chromatograph. Thanks to ABB and PACE. 

Chromatography  - The Basics - Chromatography is usually introduced as a technique for separating and/or identifying the components in a mixture. The basic principle is that components in a mixture have different tendencies to adsorb onto a surface or dissolve in a solvent. It is a powerful method in industry, where it is used on a large scale to separate and purify the intermediates and products in various syntheses - from the Royal Society of Chemistry.

Gas Chromatography Troubleshooting Guide - A useful guide for seeking out Gas Chromatograph faults - from msp.

Instrumentation of Gas Chromatography - G.A. Eiceman - Instrumentation for gas chromatography (GC) comprises well-defined components, each of which contributes to the overall chromatographic performance. Most of these components have reached a mature level of technical development after nearly 50 years of development. Nonetheless, advances are occurring in an evolutionary, not revolutionary, manner with sample handling and in refinements of detectors. One area of dramatic advance in GC instrumentation is the development of small, sophisticated, portable gas chromatographs. Each component of a gas chromatograph (columns excepted) is discussed in this paper where principles and recent developments are emphasized - from Wiley.

Encyclopedia of Analytical Chemistry - The highly-acclaimed Encyclopedia of Analytical Chemistry provides a much-needed professional level reference work for the 21st Century. The Encyclopedia is the most comprehensive analytical chemistry reference available, covering all aspects from theory and instrumentation through to applications and techniques. You have to pay to access the content.

Gas Chromatographs Rule - What Comes First--the Analyzer or the Analyzer Application? - Greg McMillan and Stan Weiner bring their wits and more than 66 years of process control experience to bear on your questions, comments, and problems - from the excellent Control Global.

The following papers are from Daniel 
Analysis of Pipeline-Quality Gas using a C9: Application (Five-Minute Analysis) - On-line chromatographs provide custody-transfer measurement of energy content in natural gas. To determine this heating value component, first we must determine component concentrations. In a standard C6+ application, this analysis is performed using two valves in a single oven (12-minute analysis time) or three valves in a single oven (four-minute analysis time). To perform this analysis to C9+, five valves are used in two different ovens (five-minute analysis time). The results from both detectors are combined in post-analysis calculations and reported together.
Analysis of Pipeline-Quality Gas using a C6+ with Trace H2S Application -Hydrogen sulfide (H2S) is a component that is often present in natural gas. There are many reasons for wanting to measure it. One of the most important reasons is that H2S is a highly toxic gas that can be deadly if breathed into the lungs. This gas is also corrosive to the pipeline. H2S mixed with H2O forms hydrosulfuric acid, which can cause pipeline metals to become brittle. Contractual obligation may require scrubbing or limiting of the H2S in natural gas before it is sold. Each pipeline company has its own acceptable limits of how much H2S can be present.

The Following are from Emerson Process Management
Choice of Gas Chromatograph Ovens and Shelters Impacts Cost of Ownership - Michael Gaura - When industry professionals scope out a new capital analyzer project, they spend time and effort evaluating the equipment to be used. In the case of gas chromatographs (GC), key capital expenses – the oven associated with the GC and the shelter that houses it – may not be considered in the final decision, often because managers do not realize they have a choice. In fact, these decisions can have a huge impact on the cost of ownership of the analysis equipment, with the potential to significantly reduce costs at initial installation, in operation and maintenance and in the execution of change orders.
The Fundamentals Of Pipeline Gas Chromatographs - Shane Hale - Gas chromatographs (GCs) are installed all over natural gas pipeline networks, providing an analysis of the flowing gas and calculating the physical properties used for the flow calculations and for custody transfer. However, a clear understanding of just how the GC works and the considerations that need to be made for the installation and operation of the GC are often lacking in the industry. This article discusses the major components of the GC and provides an understanding of the theory and practice of gas chromatography in the pipeline industry.
Perfecting Liquefied Natural Gas Analysis Techniques and Methods - S.Hale - Following these procedures will improve measurement accuracy and reliability.
Optimizing the Operation of Legacy Online Gas Chromatographs by Retrofitting Controllers - Gas chromatographs (GCs) are frequently used in pipelines for custody transfer measurement of the energy content in natural gas. Accuracy is determined by calibration-gas quality and how well the technician is able to diagnose and troubleshoot the operation of the GC over long periods of time. A general trend in industry away from specialization has made it difficult for technicians to reach a high competency level in any one area. Chromatography is a difficult field to master on a part-time basis. Advanced software tools are available to assist and train the technician in how to look beyond the basic functions and fully optimize GC operations. Training is enhanced and accuracy can be improved substantially on legacy-model gas chromatographs. Properly utilized, the potential exists to improve accuracy and extend equipment life.Energy Measurement using Ultrasonic Flow Measurement and Chromatography - Gas volume and energy metering stations using gas chromatography and ultrasonic metering are becoming a mainstream field operation and a new challenge to metering personnel. They are easy to adapt to while adding a new dimension of value to the field professional. Technicians will invariably be the link to the success of any changing technology that would survive and thrive in the real pipeline environment. Meter stations must be maintainable and provable. The system and requirements will be examined from that perspective 
BTU Analysis Using a Gas Chromatograph - This paper describes the basics of how a BTU analyzer works. In a typical natural gas application the gas is separated into eleven different components. Hexanes and heavier components such as heptane, octane, and nonane are combined together to form a single peak known as C6+. Because we separate up to these components, we call this a C6+ application.
Enhanced Performance of an Integrated Gas Chromatograph for Online Gas Analysis - The physical properties of the gas, the composition of the gas during upset, and the operation of the gas in hazardous locations can affect the analytical method development and the hardware design. The gas chromatograph must be compatible with the physical properties (e.g., the physical state) of the sample. The sample must be introduced to the gas chromatograph as a single phase. Since on-line gas chromatographs are installed at the pipeline to analyse sample continuously, the system must be designed for fast analyses and low maintenance.

Continuous Emission Monitoring

Continuous Emission Monitoring - In today's industrial world pollution, global warming and the need to protect the environment analysis of emissions is a critical tool.  ICEwebs dedicated page on this subject contains links and technical information.

Density Analysis

Accurate Liquid Phase Density on Aerated Liquid - Dan Gysling and Doug Loose - Density is one of the most widely used composition-based measurements in industrial process control. However, it is well recognized that the presence of small, but unknown levels of entrained gases can mask the density of the non-aerated component of a process mixture, resulting in an inaccurate determination of process fluid density - from Sonartrac

Gas Analysis - Coming Soon

Odorization Analysis

Principles of Odorization - Paul Minier - A discussion of odorant, odorizers, and odorization -  Monitoring is accomplished with on line analyzers, such as, titrators, analyzers, and chromatographs. Each type of instrument gives real-time information of total sulphur, or in some cases, individual mercaptan component levels. Several manufacturers use electrochemical sensors or cells while others use GC columns for detection or lead acetate tape technology. Regardless of the manufacturer, your technician must be trained on its calibration and operation. Although these instruments do not meet the Title 49 192.625 for reporting, they can play an important part of your total Odorization program. These instruments can give you real time information at the central office and in some cases, correct the odorizer levels before an incident occurs.

Oxygen Analysis

Oxygen - ICEweb's dedicated page of technical information.

PH Analysis

PH Measurement - ICEweb's comprehensive PH page which is full of technical information on this subject.

Humidity Measurement

Humidity Measurement -ICEweb's Humidity page is a great resource for a swag of information.

Mercury Analyser

Design of a Mercury Analyzer for Stack Gas - Koji ISHIKAWA - In December 2005, the Environmental Protection Agency (EPA) of the United States implemented the Clean Air Mercury Rule (CAMR), a regulation to limit the a total emission of mercury from coal-fired power stations, to attempt to reduce the mercury content in exhaust gas. . Amid growing concern for mercury monitoring, detailed is the  development of an analyzer that continuously measures total mercury in exhaust gas by oxidized mercury (Hg2+) to elemental mercury (Hg) - This technical whitepaper is courtesy of the team at IDC Technologies – for more IDC resources simply visit their website:

Oil in Water Analysis

Oil in Water Analysers

Process Analyser Sample Systems

Sample Systems - A representative sample is critical to achieve a correct analysis result. ICEweb's Sample Systems page has a wealth of information to help achieve this.

Specific Gravity

Determination of Specific Gravity of Gases: Fundamentals and Instruments - Faruk Civan - Specific gravity is one of the basic properties used for characterisation and measurement of gases. Instruments used for determining specific gravity are called gravitometers. There are also methods by which specific gravity can be determined indirectly. Accurate determination of specific gravity is essential for accurate measurement of gas flow rate - from CEESI


The following application sheets and technical papers are from Applied Analytics Inc.
Incoming Materials Validation by UV/VIS/SWNIR Absorbance; An On-line Recognition Method - Yoav Barshad and Yael S. Barshad - In the fine chemicals and the pharmaceutical industry, validating the contents of incoming materials is critical. To maintain high efficiency it is beneficial to utilize continuous online techniques. Since many of the incoming chemicals show unique UV/VIS or NIR absorbance spectra, it was the analytical technique of preference. In order to handle a variety of incoming substances a recognition method to differentiate between the “correct” substance and all other possible streams was developed. The recognition method uses a pattern recognition algorithm to give the similarity/differences between two spectra in terms of a single number. An example of such an application will be described. A diode array process UV/VIS/SWNIR (short wave near infrared) spectrophotometer was employed to differentiate between a stream of mixed xylenes and other process streams. It was shown that there are significant variations in spectral features between the xylenes and the other samples. A recognition factor was defined and used to demonstrate the effectiveness of the method. A user defined threshold value for the recognition factor was used for a continuous and automatic identification of the process stream.
Diode Array Process Analyser for Sulphur - Aaron J Rollo - this paper reviews the utilisation of spectroscopy with diode arrays, a time tested, industry accepted technology for sulphur recovery applications. One analyser with different sampling systems can be used for a variety of applications. Common applications include Hydrogen sulphide (H2S), Tail Gas, Natural Gas and Mercaptans.
Clean in Place-Monitoring Trace Impurities in a Reaction Chamber - Validation of cleaning procedures are of utmost importance to the pharmaceutical, food, and specialty chemicals industries. The following application is an example of how an industrial spectrophotometer could be applied to the development, validation, and control of a Clean In Place (CIP) process - from A
Spectrum Analysis of a Tail gas Stream - This application sheet details how the analyser measures a complete spectrum of the process and analyse the data via a calibration method to give very accurate and reliable concentration readings. In addition Standard gases can be introduced at any time to test the accuracy and reproducibility of the analyser. In the continuous operation the complete spectrum is display, this allows the operator to check the system and the validity of the actual reading - As oppose to filter based units where the operator has no access to the actual detection only to the final numbers. The tail gas stream , depending on the source, contain various amounts of sulphur. The measurements are being performed in situ while the sulphur is reduced significantly by this ‘cold-finger’ probe, no coating or plugging usually associated with sulphur streams are seen - from Applied Analytics Inc.
Purity Levels by a UV Transmittance Method (MEG and Acetonitrile) - This application sheet details analysis of purity levels for Mono Ethylene Glycol (MEG) which is a raw material in fibre production. The quality of the fibres is highly dependent on the MEG purity level. Currently most MEG manufacturers use off-line methods for MEG quality control, where a sample is withdrawn from the process stream for laboratory analysis several times a day. The same measurement can be performed online utilising an industrial spectrophotometer. 

More Applications for Spectrophotometers can be found here.

Viscosity- Coming Soon

Useful Analytical Instrumentation Books

Analytical Instrumentation - Robert E. Sherman -  In this book on process analytical technology, you will find theory and a lot of real-world, hands-on practical knowledge from authors who have more than 20 years of experience, either applying analyzers in process plants, or for process manufacturers. This volume chronicles over 50 years of process analyzer development, from its origins in the research laboratory at Ludwigshafen in the late 1930’s to a dynamic worldwide technology in the early 1990’s. Included are drawings of sample systems that work, and comments on ones that don’t work. In addition, justifications and organization guidelines on process analyzer systems are represented.

Analyser Application

Tail Gas Analyser
Online Tail Gas Analysis in Sulphur Recovery - This system monitors real-time concentrations of H2S and SO2 in the Claus process stream, computing the control parameter for a continuously reliable air demand signal - from Applied Analytics.

Measuring Odorants in Natural Gas Pipelines - Local distribution companies (LDCs) employ numerous "sniffers" who judge odorant level in the natural gas product, while generating data from field reports, customer input, and modelling programs. However, interstate pipelines span hundreds of miles that cross through various territories. Dispatching "sniffers" across vast distances is both time-consuming and costly. While "sniff testing" complies and satisfies the minimum criteria set forth in CFR, Title 49, Part 192.625, an on-line process analyzer would provide the same testing functionality with much richer quantitative data (one example: continuous trend data as opposed to discrete data points). On-line odorant analysis allows the transmission companies to schedule the minimum required visits to perform sniffing, and optimize their odorant distribution system in real-time. Secondary benefits allow them to optimize their pipeline performance by studying lag times, odorizer performance, fading effects, and other odorant issues - from Applied Analytics.

Recovery Boiler Applications
Analytical Measurements Protect Recovery Furnace and Boiler in a
Pulp and Paper Mill - Dave Joseph and Doug Simmers - Recovery Boiler operations can be improved considerably by using continuous analytical measurements. The information they collect can be used to optimize black liquor conversion and energy extraction in the furnace without compromising safety and reliability of boiler tubes and other components. The Recovery Furnace oxidizes concentrated black liquor, thereby generating feedstock for green liquor and the rest of the Kraft process, and simultaneously producing steam for millwide use. The furnace is optimized by controlling excess combustion air levels to maximize smelt recovery, prevent corrosion, and maximize steam production. The boiler is optimized for longevity by monitoring the quality of water used to produce steam. This also protects the boiler tubes against corrosion and pitting due to harmful mineral deposits. Effective analytical measurements can assist in optimizing these operations. Additionally, accurate analysis of both combustion flue gases and boiler water can be used to prevent explosive conditions - from Rosemount Analytical.

Desalination Plants
A Cost Saving Strategy for Desalination Plants - Wireless Liquid Analytical Instrumentation Comes to the Fore - As new desalination plants are built and present facilities are expanded, plant operators can realise significant cost savings by employing a recent advance in online process instrumentation – wireless technology. Two of the most promising applications for wireless technology are the measurement of pH and conductivity - from Rosemount Analytical.


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