Process Analyzer

Process Analyzer 

Training course 

Muayad Al Faour

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QMI- Quality Measurements Instruments 

In a world of cost reduction and a need for increased efficiency, people on all levels within an organisation focus on the plant wide performance of quality measurement instruments. 

Operators and maintenance personnel need high quality data and detailed information on the performance of each individual instrument. 

Management needs high quality information on the plant wide performance of QMI‘s for better process control. 

The analyser management system monitors and controls each Quality Measurement Instrument (QMI) on 

•Analytical Performance

•Availability

•Maintainability

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pH electrodes and sensors are the sensing portions of a pH measurement. Various installation options including retractable, flow thru, immersion, and direct insertion. Proper pH electrode/sensor selection is critical for optimal measurement results.

Conductivity Analyzers

What is Conductivity?

Conductivity is the measure of a solution's ability to pass or carry an electric current. The term Conductivity is derived from Ohm's Law, E=I•R; where Voltage (E) is the product of Current (I) and Resistance (R); Resistance is determined by Voltage/Current. When a voltage is connected across a conductor, a current will flow, which is dependent on the resistance of the conductor.  Conductivity is simply defined as the reciprocal of the Resistance of a solution between two electrodes.

How do we measure Conductivity?

There are two basic sensor styles used for measuring Conductivity: Contacting and Inductive (Toroidal, Electrodeless).

When Contacting Sensors are used, the conductivity is measured by applying an alternating electrical current to the sensor electrodes (that together make up the cell constant) immersed in a solution and measuring the resulting voltage. The solution acts as the electrical conductor between the sensor electrodes.

The sensor, based on a zirconium oxide cell, is mounted at the tip of the probe that is inserted in the flue duct. The resulting direct, in situ measurement provides accurate and rapid oxygen reading for combustion control optimization and emissions monitoring.

(1) Zirconia type measurement system : Concentration cell system

A solid electrolyte like zirconia exhibits conductivity of oxygen ions at high temperature.
As shown in the figure, when porous platinum electrodes are attached to both sides of the zirconia element to be heated up and gases of different partial oxygen concentrations are brought into contact with the respective surfaces of the zirconia, the device acts as an oxygen concentration cell. This phenomenon causes an electromotive force to be generated between both electrodes according to Nernst’s equation. And it is proportional oxygen concentration.

Advantage 

Can be directly installed in a combustion process such as a boiler’s flue and requires no sampling system, and response is faster.

Disadvantages :If the sample gas contains a flammable gas, a measurement error occurs (combustion exhaust gas causes almost no problem because it is completely burned).

(2)  Magnetic type measurement system : Paramagnetic system

This is one of the methods utilizing the paramagnetic property of oxygen. When a sample gas contains oxygen, the oxygen is drawn into the magnetic field, thereby decreasing the flow rate of auxiliary gas in stream B. The difference in flow rates of the two streams, A and B, which is caused by the effect of flow restriction in stream B, is proportional to the oxygen concentration of the sample gas. The flow rates are determined by the thermistors and converted into electrical signals, the difference of which is computed as an oxygen signal.

Advantages 

*Capable of measuring flammable gas mixtures that cannot be measured by a zirconia oxygen analyzer.

*Because there is no sensor in the detecting section in contact with the sample gas, the paramagnetic system can also measure corrosive gases.

*Among the magnetic types, the paramagnetic system offers a faster response time than othe systems.

*Among the magnetic types, the paramagnetic system is more resistant to vibration or shock than other systems.

Disadvantages :Requires a sampling unit corresponding to the sample gas properties or applications.

Application examples for each oxygen analyzer

Oxygen concentrations are measured for a variety of purposes, such as energy conservation, air pollution prevention, safety management, and quality control.

The following lists major application examples by measurement method.

Limiting Current type　Zirconia Oxygen AnalyzerOxygen concentration control of N2 reflow furnaces
Atmospheric control of semiconductor manufacturing equipment
N2 and air purity control for air separators
Oxygen deficiency prevention
Oxygen concentration control of glove boxes for research and development and parts machining
Oxygen concentration control of experimental clean rooms for environment, fermentation, biochemistry, etc.
Continuous measurement of flow gases during food packaging

Concentration cell system　Zirconia Oxygen AnalyzerPackage

boiler combustion control, gas fired
Combustion control of power generation boilers, gas fired
Combustion control of pulverized coal boilers
Combustion control of hot stoves for steelmaking
Heating and combustion exhaust gas control of coke ovens for steelmaking
Low-oxygen concentration control of reheating and soaking furnaces for steelmaking
Air leakage detection of sintering furnaces for steelmaking
Lime kiln combustion control
Cement kiln combustion control
Combustion control of heating furnaces for oil refinery & petrochemical industry
Naphtha cracking furnaces
Incinerator combustion control
Oxygen concentration measurement in oxygen enrichment facilities
Oxygen concentration measurement of exhaust gas from activated sludge process equipment

Dissolved Oxygen Analyzer

Dissolved oxygen refers to oxygen dissolved in water. Its concentration is expressed as the amount of oxygen per unit volume and the unit is mg/L. Biologically, oxygen is an essential element for respiration of underwater life and also acts as a chemical oxidizer. The solubility of oxygen in water is affected by water temperature, salinity, barometric pressure, etc. and decreases as water temperature rises.

Orbisphere 3655 Portable Oxygen (O₂) EC, units : ppm/ppb/ppm

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Ideal for Harsh Environments

The Orbisphere 3650 offers a robust portable system solution for oxygen measurement. The compact stainless steel construction is designed for the harsh environment of breweries, but it is also perfectly adapted for laboratory or verification purposes in other beverage applications. In addition, the 3650 can be used across a wide range of applications in the power generation, electronics and life sciences industries. Designed for use with the Orbisphere A1100 high quality oxygen sensor, these instruments provide fast, accurate and repeatable measurements in both the dissolved and gaseous phase, at line or in the laboratory. For low level applications, the specially configured Orbisphere 3655 measures to 0.1 ppb oxygen.

Simple Installation and Operation

The Orbisphere 3650 inlet tube is connected to a sample point or to a piercing device by a simple connector, making it quick and easy to install. The sample flows over the sensor membrane in the flow chamber, with an output valve controlling the sample's flow rate. The instrument's outlet tube allows the sample to drain away. The sample volume requirement is small, minimizing waste. The Orbisphere 3650 uses two C-type, NiMH or alkaline batteries. Changing the batteries is quick and easy; there is no down time for the instrument. Stored measurements are not lost if batteries go flat or are being changed.

Simple Maintenance

The use of the Orbisphere A1100 sensor with this portable instrument allows for very quick cleaning with nothing more than tap water and requires no technical skills. The sensor refurbishment (typically every 6 months) takes only 3 minutes with a pre-mounted membrane cartridge and electrolyte, eliminating any risk of incorrect membrane positioning.

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Easy Calibration

Calibration after each sensor refurbishment is recommended. A traceable and simple calibration can be done directly in air by measuring its oxygen content with the use of the built-in pressure sensor and the automatic software calculation. Alternatively, the calibration can be performed against a liquid or gaseous sample of known concentration by simply entering the gas concentration via the keyboard. The Orbisphere A1100 oxygen sensor technology reduces residual signals to negligible levels, eliminating the need for a zero point calibration and providing fast response times essential for multiple measurements. A number of different membranes are available for use with the sensor, optimizing the wide range of measurement applications

Paramagnetic system Oxygen Analyzer

Low oxygen concentration control.
Oxygen concentration control of gas containing a flammable gas
Safety control (explosion prevention) at various plants
Measurement of trace oxygen concentration in various manufacturing processes
City gas quality control

● Good for volatile samples (up to about 250 oC)

● 0.1-1.0 microliter of liquid or 1-10 ml vapor

● Can detect <1 ppm with certain detectors

● Can be easily automated for injection and data analysis

Gas Chromatography

GAS CHROMATOGRAPHY

Gas Chromatography (GC) is a technique which separateS a gas mixture to determine the presence and concentration of gases and impurities in a sample. Applied correctly, GC can measure down to ppb levels, making it well suited for use in high purity processes.

In GC, gas mixture components are separated by circulating a gas sample, using an inert carrier gas, into a flow-through circular tube known as a column. The different gas constituents are separated due to their interaction with the column material, which cause the different molecules in the sample to elute at different times. These specific retention times are detected by a sensor at the column exit, as the individual molecular properties of each gas cause it to travel through and exit at a different time.

The comparison of retention times allows users to qualitatively identify gas types by the order in which they elute from the column. If conditions are constant, a particular gas will elute with the same retention time, allowing specific gas types to be deduced from the area of the peak. In addition, the relative volume of each gas concentration can also be measured by the detector as each gas elutes from the column.

The conditions by which GC operates for a given application are invariably different and require individual optimization. The majority of GC analyzers are therefore preset at the factory, with application specific valve timings, flow and temperature settings and peak detection parameters.

Gas chromatography (GC) 

is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, or separating the different components of a mixture (the relative amounts of such components can also be determined). In some situations, GC may help in identifying a compound. In preparative chromatography, GC can be used to prepare pure compounds from a mixture.

In gas chromatography, the mobile phase (or "moving phase") is a carrier gas, usually an inert gas such as helium or an unreactive gas such as nitrogen. Helium remains the most commonly used carrier gas in about 90% of instruments although hydrogen is preferred for improved separations.The stationary phase is a microscopic layer of liquid or polymer on an inert solid support, inside a piece of glass or metal tubing called a column (an homage to the fractionating column used in distillation). The instrument used to perform gas chromatography is called a gas chromatograph (or "aerograph", "gas separator").

The gaseous compounds being analyzed interact with the walls of the column, which is coated with a stationary phase. This causes each compound to elute at a different time, known as the retention time of the compound. The comparison of retention times is what gives GC its analytical usefulness.

GC analysis

A gas chromatograph is a chemical analysis instrument for separating chemicals in a complex sample. A gas chromatograph uses a flow-through narrow tube known as the column, through which different chemical constituents of a sample pass in a gas stream (carrier gas, mobile phase) at different rates depending on their various chemical and physical properties and their interaction with a specific column filling, called the stationary phase. As the chemicals exit the end of the column, they are detected and identified electronically. The function of the stationary phase in the column is to separate different components, causing each one to exit the column at a different time (retention time). Other parameters that can be used to alter the order or time of retention are the carrier gas flow rate, column length and the temperature.

In a GC analysis, a known volume of gaseous or liquid analyte is injected into the "entrance" (head) of the column, usually using a microsyringe (or, solid phase microextraction fibers, or a gas source switching system). As the carrier gas sweeps the analyte molecules through the column, this motion is inhibited by the adsorption of the analyte molecules either onto the column walls or onto packing materials in the column. The rate at which the molecules progress along the column depends on the strength of adsorption, which in turn depends on the type of molecule and on the stationary phase materials. Since each type of molecule has a different rate of progression, the various components of the analyte mixture are separated as they progress along the column and reach the end of the column at different times (retention time). A detector is used to monitor the outlet stream from the column; thus, the time at which each component reaches the outlet and the amount of that component can be determined. Generally, substances are identified (qualitatively) by the order in which they emerge (elute) from the column and by the retention time of the analyte in the column.

Detectors

The most commonly used detectors are the flame ionization detector (FID) and the thermal conductivity detector (TCD). Both are sensitive to a wide range of components, and both work over a wide range of concentrations. While TCDs are essentially universal and can be used to detect any component other than the carrier gas (as long as their thermal conductivities are different from that of the carrier gas, at detector temperature), FIDs are sensitive primarily to hydrocarbons, and are more sensitive to them than TCD. However, a FID cannot detect water. Both detectors are also quite robust. Since TCD is non-destructive, it can be operated in-series before a FID (destructive), thus providing complementary detection of the same analytes.

Other detectors are sensitive only to specific types of substances, or work well only in narrower ranges of concentrations. They include:

•Thermal Conductivity detector (TCD), this common detector relies on the thermal conductivity of matter passing around a tungsten -rhenium filament with a current traveling through it. In this set up helium or nitrogen serve as the carrier gas because of their relatively high thermal conductivity which keep the filament cool and maintain uniform resistivity and electrical efficiency of the filament. However, when analyte molecules elute from the column, mixed with carrier gas, the thermal conductivity decreases and this causes a detector response. The response is due to the decreased thermal conductivity causing an increase in filament temperature and resistivity resulting in fluctuations in voltage.Detector sensitivity is proportional to filament current while it is inversely proportional to the immediate environmental temperature of that detector as well as flow rate of the carrier gas.

Flame Ionization detector (FID), in this common detector electrodes are placed adjacent to a flame fueled by hydrogen / air near the exit of the column, and when carbon containing compounds exit the column they are pyrolyzed by the flame.This detector works only for organic / hydrocarbon containing compounds due to the ability of the carbons to form cations and electrons upon pyrolysis which generates a current between the electrodes. The increase in current is translated and appears as a peak in a chromatogram. FIDs have low detection limits (a few picograms per second) but they are unable to generate ions from carbonyl containing carbons. FID compatible carrier gasses include helium, hydrogen, nitrogen, and argon

Detection

→The effluent from the column is mixed with hydrogen and air, and ignited. Organic compounds burning in the flame produce ions and electrons which can conduct electricity through the flame. A large electrical potential is applied at the burner tip, and a collector electrode is located above the flame. The current resulting from the pyrolysis of any organic compounds is measured. FIDs are mass sensitive rather than concentration sensitive; this gives the advantage that changes in mobile phase flow rate do not affect the detector's response. The FID is a useful general detector for the analysis of organic compounds; it has high sensitivity, a large linear response range, and low noise. It is also robust and easy to use, but unfortunately, it destroys the sample.

Sample size and injection technique

Sample injection

The rule of ten in gas chromatography

The real chromatographic analysis starts with the introduction of the sample onto the column. The development of capillary gas chromatography resulted in many practical problems with the injection technique. The technique of on-column injection, often used with packed columns, is usually not possible with capillary columns. The injection system in the capillary gas chromatograph should fulfil the following two requirements:

1.The amount injected should not overload the column.

2.The width of the injected plug should be small compared to the spreading due to the chromatographic process. Failure to comply with this requirement will reduce the separation capability of the column. As a general rule, the volume injected, Vinj, and the volume of the detector cell, Vdet, should be about 1/10 of the volume occupied by the portion of sample containing the molecules of interest (analytes) when they exit the column.

Some general requirements which a good injection technique should fulfill are:

•It should be possible to obtain the column’s optimum separation efficiency.

•It should allow accurate and reproducible injections of small amounts of representative samples.

•It should induce no change in sample composition. It should not exhibit discrimination based on differences in boiling point, polarity, concentration or thermal/catalytic stability.

•It should be applicable for trace analysis as well as for undiluted samples.

However, there are a number of problems inherent in the use of syringes for injection, even when they are not damaged:

•Even the best syringes claim an accuracy of only 3%, and in unskilled hands, errors are much larger

•The needle may cut small pieces of rubber from the septum as it injects sample through it. These can block the needle and prevent the syringe filling the next time it is used. It may not be obvious of what happened.

•A fraction of the sample may get trapped in the rubber, to be released during subsequent injections. This can give rise to ghost peaks in the chromatogram.

•There may be selective loss of the more volatile components of the sample by evaporation from the tip of the needle.

Column selection

The choice of column depends on the sample and the active measured. The main chemical attribute regarded when choosing a column is the polarity of the mixture, but functional groups can play a large part in column selection. The polarity of the sample must closely match the polarity of the column stationary phase to increase resolution and separation while reducing run time. The separation and run time also depends on the film thickness (of the stationary phase), the column diameter and the column length.

Column temperature and temperature program

A gas chromatography oven, open to show a capillary column

The column(s) in a GC are contained in an oven, the temperature of which is precisely controlled electronically. (When discussing the "temperature of the column," an analyst is technically referring to the temperature of the column oven. The distinction, however, is not important and will not subsequently be made in this article.)

The rate at which a sample passes through the column is directly proportional to the temperature of the column. The higher the column temperature, the faster the sample moves through the column. However, the faster a sample moves through the column, the less it interacts with the stationary phase, and the less the analytes are separated.

In general, the column temperature is selected to compromise between the length of the analysis and the level of separation.

A method which holds the column at the same temperature for the entire analysis is called "isothermal." Most methods, however, increase the column temperature during the analysis, the initial temperature, rate of temperature increase (the temperature "ramp"), and final temperature are called the "temperature program."

A temperature program allows analytes that elute early in the analysis to separate adequately, while shortening the time it takes for late-eluting analytes to pass through the column.

Qualitative analysis

Generally chromatographic data is presented as a graph of detector response (y-axis) against retention time (x-axis), which is called a chromatogram. This provides a spectrum of peaks for a sample representing the analytes present in a sample eluting from the column at different times. Retention time can be used to identify analytes if the method conditions are constant. Also, the pattern of peaks will be constant for a sample under constant conditions and can identify complex mixtures of analytes. However, in most modern applications, the GC is connected to a mass spectrometer or similar detector that is capable of identifying the analytes represented by the peaks.

Quantitative Analysis 

The area under a peak is proportional to the amount of analytepresent in the chromatogram. By calculating the area of the peak using the mathematical function of integration, the concentration of an analyte in the original sample can be determined. Concentration can be calculated using a calibration curve created by finding the response for a series of concentrations of analyte, or by determining the relative response factor of an analyte. The relative response factor is the expected ratio of an analyte to an internal standard (or external standard) and is calculated by finding the response of a known amount of analyte and a constant amount of internal standard (a chemical added to the sample at a constant concentration, with a distinct retention time to the analyte).

The peak height is proportional to the amount 

of material eluting from the column at any given time,

The area under the peak is a measure of the total 

amount of material that has eluted from the column.

Electronic integrators are used for area measurement

in commercial GCs. We will be using ALGEBRA.  

Determination of the Amount 

of Sample Components Present

BL983318-1 TDS Mini Controller (0.00 to 10.00 ppt)

A TDS Meter indicates the Total Dissolved Solids (TDS) of a solution, i.e. the concentration of dissolved solid particles. Dissolved ionized solids, such as salts and minerals, increase the electrical conductivity (EC) of a solution. Because it is a volume measure of ionized solids, EC can be used to estimate TDS.

1. "Dissolved solids" refer to any minerals, salts, metals, cations or anions dissolved in water. This includes anything present in water other than the pure water (H20) molecule and suspended solids. (Suspended solids are any particles/substances that are neither dissolved nor settled in the water, such as wood pulp.)
 

2. In general, the total dissolved solids concentration is the sum of the cations (positively charged) and anions (negatively charged) ions in the water.
 

3. Parts per Million (ppm) is the weight-to-weight ratio of any ion to water. 
 

4. Conductivity is usually about 100 times the total cations or anions expressed as equivalents. Total dissolved solids (TDS) in ppm usually ranges from 0.5 to 1.0 times the electrical conductivity. 

UPW Boron Analyzer

With a limit of detection of 15 parts-per-trillion boron and the ability to run up to 10 samples per hour, the Sievers UPW Boron Analyzer makes continuous boron monitoring in ultrapure water very affordable and remarkably convenient. The Sievers UPW Boron Analyzer even exceeds ICP-MS performance (see Progress Report on New On-line Boron Analyzer Research), and does it at a fraction of the cost. A true "plug-and-play" instrument, the Boron Aanalyzer can be installed in less than an hour, requires no skilled or trained operator, and provides the sensitivity and accuracy of ICP-MS or on-line Ion Chromatography. A built-in multiplexor allows for monitoring of up to four sample streams with customizable settings for each stream.

Orsat gas analyser

An Orsat gas analyser is a piece of laboratory equipment used to analyse a gas sample (typically fossil fuel flue gas) for its oxygen, carbon monoxide and carbon dioxide content. Although largely replaced by instrumental techniques, the Orsat remains a reliable method of measurement and is relatively simple to use.

The apparatus consists essentially of a calibrated water-jacketed gas burette connected by glass capillary tubing to two or three absorption pipettes containing chemical solutions that absorb the gasses it is required to tmeasure. For safety and portability, the apparatus is usually encased in a wooden box.

The absorbents are:

Potassium Hydroxide (Caustic Potash)

Alkaline pyrogallol

ammoniacal Cuprous chloride

The base of the gas burette is connected to a levelling bottle to enable readings to be taken at constant pressure and to transfer the gas to and from the absorption media. The burette contains slightly acidulated water with a trace of chemical indicator (typically methyl orange) for colouration.

Mercury traces contained in natural gas can cause severe damage to gas processing plants due to corrosion effects. 

On-Line Analyzer Determines Gasoline Vapor Pressure

ON-LINE is a process monitoring analyzer for the determination of the vapor pressures of gasoline, crude oil, LPG and NPG. Also, the vapor-liquid ratio (LVR) of gasoline can be measured. 

Reid vapor pressure (RVP) is a common measure of the volatility of gasoline. It is defined as the absolute vapor pressure exerted by a liquid at 37.8 °C (100 °F) as determined by the test method ASTM-D-323.

Volatility is the property of a liquid fuel that defines its evaporation characteristics. RVP is an abbreviation for "Reid vapor pressure," a common measure of and generic term for gasoline volatility. EPA regulates the vapor pressure of gasoline sold at retail stations during the summer ozone season (June 1 to September 15) to reduce evaporative emissions from gasoline that contribute to ground-level ozone and diminish the effects of ozone-related health problems.

EPA established a two-phase reduction in summertime commercial gasoline volatility. These rules reduce gasoline emissions of volatile organic compounds (VOC) that are a major contributor to ground-level ozone (smog). Phase I was applicable to calendar years 1989 through 1991. Depending on the state and month, gasoline RVP was not to exceed 10.5 pounds per square inch (psi), 9.5 psi, or 9.0 psi. Phase II is applicable to 1992 and later calendar years.

Specific Gravity Analyzer 

The BA-GSG is an online process analyzer for continuous, reliable and accurate measurement of specific gravity (density) of a gas mixture. The instrument is available for operation in an explosive atmosphere (ATEX) environment.

The BA-GSG is equipped with a cell for measuring specific gravity of the process gas in a specially designed sample chamber, using a modulated acoustic signal.

A pressurized enclosure is provided with a protective purge system (N2 gas) and an optional Vortex cooler.

Features:

•Direct Specific Gravity (density) measurement

•Reduced sensitivity to vibration or pressures

•Multi-functional computer operation

•Reliable & accurate measurement

•Multi-parameter options available

•No regular maintenance required

H2S Analyzer

The petrochemical, gas processing, and gas pipeline industry has required an accurate, dependable, low maintenance, and cost-effective sulfur H2S analyzer for quality and process control purposes

The sulfur sample is precisely metered into a continuous flowing stream of hydrogen gas. The sample and hydrogen are heated in the furnace up to 1,315° C resulting in thermal cracking of the sulfur that are reduced to short chain hydrocarbons. These reactions result in the formation of H2S. After complete humidification of the sample, the H2S comes in direct contact with the lead acetate tape and produces a darkening of lead sulfide that is immediately measured by the photodiode/LED optics and rate-of-reaction digital electronics to provide an accurate and reproducible total sulfur and H2S analysis with PPB or PPM sensitivity up to 100%. The LCD display provides the current reading, any alarm condition, procedure prompts (i.e., calibration procedure), and failure indicators (local and remote capability). Quality materials are selected for their compatibility and utilized through fabrication. Special attention is given to wetted parts that come in contact with the process stream and are selected to be non-reactive with H2 S/sulfur.

H2S in Crude Oil Analyzer

 H2S in crude oil analyzer, the ability to analytically quantify H2S in light, medium & heavy crude oil and condensate is greatly enhanced with the Sample Transfer Stripper (STS) utilizing exclusive ASI Membrane Technologies and rateometric-colorimetric detection technology. This principle of operation is described in various ASTM methods including D4084-82, D4468-85, and D4045-81.

The effective process for measuring H2S in crude oil involves representatively stripping the H2S vapor from the liquid for precise measurement in the gas phase.

The principle of operation is based on a continuous, free-flowing liquid sample into the heated Sample Transfer Stripper (STS) unit which separates the liquids from the H2S gas sample, based in part on Henry’s Law. 

H2S free carrier air then sweeps the H2S sample to the H2S specific detector for quantitative analysis in ppb, ppm, or percent levels. The analyzer does not require zero or span field calibrations. The detection technology is based on chemically specific density changes and is the only detection method that is specific only to H2S.

Hydrocarbon VOC in Water Analyzer

Hydrocarbon VOC in water analyzer | The ability to analytically quantify total hydrocarbons and volatile organic compounds (VOCs) in cooling towers, heat exchangers, holding ponds, produced water, run-off water, and waste water 

The VOC in water The analyzer measures aliphatic and aromatic hydrocarbons (including important carcinogenic compounds BTEX like benzene, toluene, and xylene

The liquid sample continuously flows into the analyzer and into the heated Sample Transfer Stripper unit which effectively strips the VOC hydrocarbons from the water and into the carrier air based in part on Henry’s Law. The carrier air then sweeps the VOC hydrocarbons to the metal-oxide sensor or G.C. for quantitative analysis in ppb, ppm, or up to saturation levels.The advanced transmitter electronics quantifies and displays the values on the back-lit LCD display, 4-20mA output loop or communicates via RS-485 Modbus. Remote and Web based monitoring and control of the analyzer is available.

Oil in Water Analyzer

The analyzer accurately measures total hydrocarbons including aliphatic and aromatic hydrocarbons. Alternative oil in water monitors utilizing the UV Fluorescence methods do not have the ability to measure aliphatic compounds.

Furthermore, the UV Fluorescence method suffers from cross-sensitivity with components in the water not intended to be measured, such as debris and contamination. This gives false high readings and false high alarms. The on-line analysis offered by the Model 204 is economically superior to inaccurate laboratory analyzers where unstable grab samples result in oil deterioration that produce analytical errors.

The liquid sample continuously flows into the analyzer and into the heated Sample Transfer Stripper unit which effectively strips the hydrocarbons from the oil in the water based in part on Henry’s Law. The carrier air then sweeps the hydrocarbons to the metal-oxide sensor for quantitative analysis in ppb or ppm levels. The advanced transmitter electronics quantifies and displays the values on the back-lit LCD display, 4-20mA output loop and can communicates via RS-485 Modbus. Remote and Web based monitoring and control of the analyzer is available. The optional ‘True’ Liquid Validation System by PermTube is utilized to verify proper operation of the entire analyzer – not just the sensor – with just a flip of a switch or remote activation.

Flue Gas & Emissions Analyzers

Furnaces, heaters, and boilers burn fuel in the presence of oxygen to produce heat. Achieving an intelligent balance of fuel and air will provide the most efficient combustion and highest cost savings.

Measuring the exhaust gas is an excellent way to optimize fuel and air input. A flue gas analyzer will enable you to measure the concentrations of various gases and adjust burners on a boiler to help achieve optimal combustion.

Efficient combustion also reduces emission of pollutants such as nitric oxide (NO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and particulate matter. A gas analyzer will help measure various gas pollutants in the exhaust for environmental reasons. One term that frequently arises in this application is ‘CEMS’.

CEMS is an acronym for Continuous Emissions Monitoring System.

Total Organic Carbon (TOC) measurement is commonly used to determine the degree of organic contamination in water.

Total Organic Carbon (TOC) is an indirect measure of organic molecules present in water and measured as carbon. Organic molecules are introduced into the water from the source water, from purification, and from distribution system materials. TOC is measured for both process control purposes and to satisfy regulatory requirements.

TOC Analyzer 

Analytical technologies utilized to measure TOC share the objective of completely oxidizing the organic molecules in an aliquot of sample water to carbon dioxide (CO2), measuring the resultant CO2 concentration, and expressing this response as carbon concentration. All technologies must discriminate between the inorganic carbon, which may be present in the water from sources such as dissolved CO2 and bicarbonate, and the CO2 generated from the oxidation of organic molecules in the sample.

One approach used to measure TOC involves subtracting the measured inorganic carbon (IC) from the measured total carbon (TC), which is the sum of organic carbon and inorganic carbon:

TOC = TC – IC.

Plant water (washing water, cooling water, recovered water, boiler water, condensate, etc.)

•Continuous monitoring of water used in a plant.

•Continuous monitoring of pure boiler water assists in the detection of anomalies, such as damaged pipes.

•The short measuring cycle (4 minutes minimum) of the combustion-type TOC analyzer achieves more rapid detection of anomalies.

*1 The TOC-COD conversion formula must be determined separately.
*2 With attached option

Conductometric Technologies

Conductometric TOC detectors measure CO2 in the liquid phase. The two conductometric type detectors are Direct Conductometric and Membrane (or Selective) Conductometric. The two conductometric-type detectors have stable calibration and high sensitivity. The primary difference between the two conductometric types is that the direct detector is susceptible to interference from ionic contamination, acids, bases, and halogenated organics.

In the membrane-based conductometric method, the membrane is a protective barrier to interfering ions, enabling the analysis of CO2 only. The result is a more accurate TOC reading.

Aurora Moisture Analyzer

Aurora moisture analyzers provide moisture measurement from low PPM to % levels. The Aurora analyzers have an intuitive interface that makes them easy to learn, configure and operate.

With a local service team to support them, you have the confidence of knowing that Aurora TDLAS analyzers are always ready for immediate moisture measurement. With power and gas lines easily connected the Aurora moisture analyzer provides a wide range of reliable measurement with accuracy and fast response you need for immediate alerts to process upsets or out-of-compliance moisture concentrations.

PM880 Portable Hygrometer / Moisture Analyzer

The PM880 AC Hygrometer is a portable system for measuring moisture/humidity content of industrial gases and liquids. The PM880 was designed to withstand the most demanding applications. Utilizing the aluminum oxide moisture sensor, the PM880 can express the absolute humidity of gases and liquids in multiple units of measurement.

This hygrometer is compact, lightweight and easy to use being especially designed for portable use. It's easy to read LCD screen displays moisture readings in dew point (°C or °F), ppmv, ppmw, lb/MMSCF (natural gas) and many other unit options.

The PM880 AC can measure moisture in gases and non-aqueous liquids. It can store up to 60 log/site files with simple programming via graphic user interface. This system can be used in conjunction with Moisture Images Series (MIS), TF and M Series moisture probes ideal for use on industrial gases, plant/facility maintenance and chemical and petrochemical plants.

What is Density

The density of a material is defined as its mass per volume.

The most common units for density are the SI unit kilogram per cubic meter (kg/m³) and the cgs unit gram per cubic centimeter (g/cm³).

Density meter 

Digital density meters is based on Archimedes' principle, combined with the microelectronics technology. The liquid sample is placed into an oscillating U-tube, and measure/calculate the density of sample.

The measurement is started since the exciting vibration of the U-tube, and the frequency is measured by a piezoelectric or electromagnetic device with conversions. Since the U-tube oscillation frequency will be related to the mass of sample. When the vibration frequency and the density is simply a  linear relationship, so, measuring the vibration frequency of oscillating U-tube result the accurate density value.

What is Specific Gravity

For historical reasons the density is often expressed as specific gravity (SG) or relative density (SR) which is a dimensionless quantity as it is the ratio of two densities.

If the reference is not exactly stated it is normally assumed to be be water. As the density depends on temperature, the specific gravity depends on the temperatures to which the densities of the substance and the reference relate. The two temperatures are specified by the notation (Ts/Tr) with Ts representing the temperature at which the sample's density has been determined and Tr the temperature at which the reference density is specified. Commonly used are for example SG(20°C/20°C) and SG(20°C/4°C).

           Chlorine Analyzer 

Chlorine analysers from Pi are used in many applications requiring the measurement and control of online residual chlorine levels in water. The HaloSense range is suitable for total or free residual chlorine monitoring or control applications in potable water, seawater, process water, swimming pool water, waste water, food washing, paper and pulp, etc.

The following are available in the HaloSense range;

•Online free and total chlorine 0.01-2 ppm, 0.01-5 ppm, 0.01-10 ppm, 0.01-20 ppm, 0.01-200 ppm (free chlorine only)

•Online residual chlorine in seawater analysers (free or total bromine) 0.01-2 ppm, 0.01-5 ppm, 0.01-10 ppm, 0.01-20 ppm

•Online zero chlorine  (designed to measure the absence of free chlorine) 0.01-2 ppm for applications such as post activated carbon and pre-RO monitoring.

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The membraned amperometric sensors are enhanced with a third, reference electrode which eliminates zero drift. (NB. These chlorine sensors are often known as polarographic sensors although this is a misuse of the word polarographic). Its unique design means that pH compensation is not usually required at all, completely eliminating reagents.
The free chlorine sensors used by the analysers are largely pH independent meaning that the measurements are bufferless and reagentless. They are amperometric sensors and show remarkable sensitivity and stability. For those needing to measure chlorine at high pH (>pH 8.5) on variable pH water it is possible to provide pH compensation from either a pH sensor connected to the transmitter or from an external pH meter.

The sensors work by separating the electrodes that perform the measurement from the sample, by a membrane. This membrane allows the free residual chlorine (HOCl and OCl–) or the total residual chlorine (HOCl and OCl– plus chloramines) through the membrane. Inside the sensor the dissolved chlorine meets the electrolyte which is at a low pH. This converts the majority of the OCl– to HOCl. The HOCl is reduced at the gold working electrode and the current generated is proportional to the chlorine present, and the instrument gives a reading in ppm or mg/l.

This technique is the most advanced method of continuous chlorine measurement and has many benefits to the user including a very stable online measurement and better dosing control.

The HaloSense range is bufferless and reagent free, meaning that it has a low total cost of ownership and with maintenance intervals at 3 or even 6 months. HaloSense is fast becoming the instrument of choice for the engineer who wants the best instrument at the best price.

Viscosity measurement 

Viscosity is a quantitative measure of a fluid’s resistance to flow.

Capillary Viscometers

•It gives the ‘kinematic viscosity’ of the fluid. It is based on Poiseuille’s law for steady viscous flow in a pipe.

Rotational Viscometers

•These viscometer give the value of the ‘dynamic viscosity’.

•It is based on the principle that the fluid whose viscosity is being measured is sheared between two surfaces.

•In these viscometers one of the surfaces is stationary and the other is rotated by an external drive and the fluid fills the space in between.

•The measurements are conducted by applying either a constant torque and measuring the changes in the speed of rotation or applying a constant speed and measuring the changes in the torque.

•There are two main types of these viscometers: rotating cylinder and cone-on-plate viscometers

Effects of temperature

•The viscosity of liquids decreases with increase the  temperature.

•The viscosity of gases increases with the increase the temperature.

Effects of temperature

•The lubricant oil viscosity at a specific temperature can be either calculated from the viscosity - temperature equation or obtained from the viscosity-temperature ASTM chart.

Viscosity index

•An entirely empirical parameter which would accurately describe the viscosity- temperature characteristics of the oils.

•The viscosity index is calculated  by the following formula:

                VI = (L - U)/ (L - H) * 10

where ,    

VI is viscosity index

U is  the kinematic viscosity

  of oil of interest

L and H are the kinematic

  viscosity  of the reference oils

                            

                                                                                                                   Fig . Shows the evaluation of viscosity index

Effects of pressure

•Lubricants  viscosity increases with pressure.

•For most lubricants this effect is considerably largest  than the other effects when the pressure is significantly above atmospheric.

Applications

•Selection of lubricants for various purpose.

   - we can choose an optimum range of viscosity for engine oil.

   - for high load and also for speed operation high viscous lubricants is required.

•In  pumping operation

   - for high viscous fluid high power will require.

   - for low viscous fluid low power will require.

•In making of blend fuel

   - less viscous fuels easy to mix.

•In the operation of coating and printing.