Analytical Instrumentation

Bela G. Liptak

• Publisher: CRC Press
• Year: 2018
• eBook ISBN: 9781351466516
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

Analytical Instrumentation examines analyzers for detecting pollutants and other hazardous matter, including carbon monoxide, chlorine, fluoride, hydrogen sulfide, mercury, and phosphorous. Also covers selection, application, and sampling procedures.

1 Analyzer Application and Selection

B.G. LIPTÁK (1972, 1982, 1993)

As the end of the century approaches, analysis has moved out of the laboratory and become an on-line measurement. This move was essential for continuous quality control, which necessitates the closed-loop control of composition. In order to place the analyzers into the pipelines, they had to be made simple and reliable. The new generation of on-stream analyzers are similar in appearance and ruggedness to everyday pressure and temperature transmitters and are of the probe form, requiring no sampling for their operation. The use of probe-type analyzers eliminates both the transportation lag and the interference with sample integrity which are both present in analyzers which require sampling.

More and better analyzers are needed to improve productivity and to increase the competitive and sophisticated nature of industry. A plant may operate at a profit or at a loss, depending on its ability to increase the efficiency (by only a few percentage points) of converting feeds into products. This can be done only if the operators know what is flowing in the pipelines and are aware of the rates of flow. This represents a higher level of sophistication compared to laboratory analysis of grab samples, which was previously considered to be sufficient.

Another factor in more and better analyzers is the new generation of control systems that replaced the regulatory and feedback concepts with adequate, feedforward and optimizing modes of control, targeting improved quality and energy conservation as its major goals. The demand for more and better analyzers is reinforced by the growing concern about environmental pollution and the associated need to enforce safety standards by detecting the concentrations of various pollutants.

That there is need for more and better analyzers does not mean that their application is, or ever will be, a simple, routine task. An analyzer system will fulfill its expectations only if careful planning and evaluation precede its purchase, and if the users realize that if an expensive analyzer is worth purchasing, it is also worth calibrating and maintaining after installation. Another important factor is the operator’s acceptance, which depends largely on training and familiarization. The introduction of self-diagnosing and self-calibrating analyzers is a major contribution to improved operators’ acceptance.

In this section a few examples are given of the newer online analyzers, followed by a discussion of analyzer selection and application. The section continues with a description of the most common categories of analyzers: the radiant energy, the electrochemical, and the inferential property types. The section concludes with some comments on analyzer locations and maintenance.

IN-LINE ANALYZERS AND PROBES

In addition to microprocessor-based self-diagnostics, self-calibration, and modular construction to simplify maintenance, the most important common feature of modern analyzers is their probe format. Probe-type analyzers have been used for a long time to measure pH, conductivity, selective ion, dissolved oxygen, relative humidity, residual chlorine, oxidation-reduction potential (ORP), differential vapor pressure, corrosion, and many other variables. One of the newer analyzer probes are the fiber-optic probes (FOPs), which use fiber-optic waveguides to return the process-modified light from the probe to the spectrum analyzer instrument located at some distance away, usually in a control room (Figure 1a). FOPs can acquire data on spectral absorbance, di...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• CONTRIBUTORS
• INTRODUCTION
• 1 ANALYZER APPUCATION AND SELECTION
• 2 ANALYZER SAMPLING—PROCESS SAMPLES
• 3 ANALYZER SAMPLING—STACK PARTICULATES
• 4 AIR QUALITY MONITORING
• 5 BIOMETERS
• 6 BIOCHEMICAL OXYGEN DEMAND (BOD), CHEMICAL OXYGEN DEMAND (COD), AND TOTAL OXYGEN DEMAND (TOD)
• 7 CALORIMETERS
• 8 CARBON DIOXIDE
• 9 CARBON MONOXIDE
• 10 CHLORINE
• 11 CHROMATOGRAPHS—GAS
• 12 CHROMATOGRAPHS—LIQUID
• 13 COAL ANALYZERS
• 14 COLORIMETERS
• 15 COMBUSTIBLES
• 16 CONDUCTIVITY ANALYZERS
• 17 CONSISTENCY ANALYZERS
• 18 CORROSION MONITORING
• 19 DIFFERENTIAL VAPOR PRESSURE SENSOR
• 20 DIOXIN ANALYSIS
• 21 ELEMENTAL MONITORS
• 22 FIBER-OPTIC PROBES
• 23 FLUORIDE ANALYZERS
• 24 HYDROCARBON ANALYZERS
• 25 HYDROGEN SULFIDE
• 26 INFRARED ANALYZERS
• 27 ION-SELECTIVE ELECTRODES
• 28 MASS SPECTROMETERS
• 29 MERCURY IN AIR
• 30 MERCURY IN WATER
• 31 MOISTURE IN AIR: HUMIDITY AND DEW POINT
• 32 MOISTURE IN GASES AND LIQUIDS
• 33 MOISTURE IN SOLIDS
• INDEX