Deep-Sea Gas Analyzers

The Deep-Sea Gas Analyzer provides an accurate measurement of a variety of gases at depths of up to 2500 meters. The instrument employs a membrane gas extractor and is capable of measuring virtually any gas in LGR’s catalog, including CH4, CO2, and various stable isotopomers. Self-sustained, remote operation is possible using the internal battery, gas handling system, and data storage. Possible applications include carbon sequestration in ocean waters, methane-hydrate studies, and hydrothermal-vent effluent analysis.
As described in the Theory Section (on www.lgrinc.com), the measurement strategy is based on high-resolution direct-absorption spectroscopy. As a result, the instrument is self-calibrating and provides an absolute, accurate gas concentration without reference standards. An internal computer can store data practically indefinitely for applications requiring unattended long-term standalone operation. These analyzers can also send real-time data to a data logger through analog, digital (RS232), and Ethernet outputs.

Gas Analyzer

The Thermal and Evolved Gas Analyzer (TEGA) is a scientific instrument aboard the Phoenix spacecraft. TEGA's design is based on experience gained from the failed Mars Polar Lander. Soil samples taken from the Martian surface by the robot arm are eventually delivered to the TEGA, where they are heated in an oven to about 1,000ºC. This heat causes the volatile compounds to be given off as gases which are sent to a mass spectrometer for analysis. This spectrometer is adjusted to measure particularly the isotope ratios for hydrogen, oxygen, carbon, nitrogen, and heavier gases. Detection values as low as 10 parts per billion. The Phoenix TEGA has 8 ovens, which are enough for 8 samples.

A residual gas analyzer (RGA) is a small and usually rugged mass spectrometer, typically designed for process control and contamination monitoring in the semiconductor industry. Utilizing quadrupole technology, there exists two implementations, utilizing either an open ion source (OIS) or a closed ion source (CIS). RGAs may be found in high vacuum applications such as research chambers, surface science setups, accelerators, scanning microscopes, etc. RGAs are used in most cases to monitor the quality of the vacuum and easily detect minute traces of impurities in the low-pressure gas environment. These impurities can be measured down to 10 − 14 Torr levels, possessing sub-ppm detectability in the absence of background interferences.

RGAs would also be used as sensitive in-situ, helium leak detectors. With vacuum systems pumped down to lower than 10 - 5Torr—checking of the integrity of the vacuum seals and the quality of the vacuum—air leaks, virtual leaks and other contaminants at low levels may be detected before a process is initiated.

Brimrose NIR Analyzer

A new series of miniature near-infrared (NIR) spectrometers is said to offer a cost-effective tool for inspecting incoming raw materials and product quality control. Compact, battery-powered Model 5030 ATOF-NIR Portable Analyzer from Brimrose Corp. of America, Baltimore, allows laboratory tests to be performed anywhere in a plant environment. The instrument, which sells for $28,000 (compared with $40,000 for larger units), is reportedly insensitive to ambient light, vibration, dust, and dirt. Its design allows for quick switchover from solids to liquids, and results appear instantly on its LCD. Applications include material identification or measurement of moisture content and active-ingredient levels. Once the instrument is calibrated, it reportedly can be used by an inexperienced operator.

Tytronic Sentinel Amine Analyzer

APPLICATION The Tytronics Sentinel Amine Analyzer is an online process analyzer that is capable of measuring acid gas loading in both rich and lean amines. It can be used to measure H2S content in amines (as sulphide), total acid gas loading (both CO2 and H2S), as well as amine strength. Multiple analyzers may be required depending on the number of analyte measurements, concentration range and distance between sampling points. PRINCIPLE OF OPERATION The Sentinel analyzer is a potentiometric titrator which uses an electrode to monitor changes in ion activity in the solution during the addition of a titrant, referred to as titration. An equivalence point or endpoint is reached when the ions in solution have completely reacted or complexed with the ions supplied through the titrant addition (there is no further ion activity). At the equivalence point the concentration and volume of the titrant solution added to the reaction cell determines the equivalent concentration corresponding to the analyte of interest. It is this titration technique that is used to determine three main analytes of interest in the amine samples. These are as follows: Amine Strength Determination - To know the exact loading of the amine, it is necessary to know the amine strength, a measure of the percentage by weight of an amine solution that is amine. This measurement is carried out using a color titration of lean amine. Total Acid Gas Loading - The acid gas loading is determined by titration of the lean or loaded amine with a base, with the endpoint determined using pH measurement. H2S loading - H2S loading is determined by potentiometric titration of the lean or loaded amine using a sulphide selective ISE. FEATURES AND BENEFITS If one of each amine analyzer variant is installed, the analog outputs from each unit can be combined in a data collection system to get a complete set of measurements for each stream - amine strength, H2S concentration, and CO2 concentration. Regenerate amine only when necessary based on loading, reducing energy costs for regeneration and extending amine life. Calibration based on lab results - monthly laboratory measurements of the parameters of interest are used to calibrate the analyzer Reduced regenerator steam consumption by operating with residual H2S that ensures specification sweet gas instead of over-stripping to provide a safety margin Reduced amine loss through carry-over Reduced plant corrosion

Infra-Red CO2, CH4, and CO Analyzer

A Low Drift, High Accuracy Analyzer Galvanic Applied Sciences Inc. now offers CO2, CH4 and CO measurement technology. The sensor is based on true dual wavelength infrared technology with no moving parts. The result is a low drift, high accuracy analyzer, with a fast response time and low power consumption. Low cost Accuracy Ease of use Reliability Specific

Infrared Analyzer

INFRARED ANALYZER

The above diagram provides a graphic representation of the basic design of an infrared analyzer which is used to measure breath alcohol concentrations. The design is based on the fact that specific wavelengths of infrared energy are absorbed by ethyl alcohol molecules. In its simplest form, the instrument's detector measures the change in the amount of a specific wavelength of infrared energy that passes from the infrared source (lamp), through the sample chamber and filter wheel to the detector. The change in response on the detector, as a breath sample is submitted to the sample chamber , is monitored and analyzed by a processor in the instrument. The change in the signal is used to calculate an alcohol concentration

The difference between the amount of infrared energy that reaches the detector when the sample chamber is free of compounds that absorb the infrared energy and the amount of infrared energy that reaches the detector when a subject's breath sample is within the sample chamber, provides an indication of the concentration of the absorbing substances in the sample . If ethanol was the only molecule found in a breath sample that would absorb energy at the wavelength being recorded by the detector, the calculated difference in infrared energy reaching the detector could be used by itself to establish the concentration of alcohol in the breath sample. Unfortunately this is not always the case.

In order to deal with the lack of specificity, it is important that the primary wavelength of infrared energy used to measure the concentration of alcohol is selected based upon its limited cross sensitivity to other substances that are commonly found in the human breath. The spinning filter wheel in the diagram above is used to modulate the light through several different filters allowing different wavelengths of infrared energy to be transmitted to the detector for analysis. The secondary wavelengths of energy are selected based upon the interfering compounds that could be found in a human breath sample. If these compounds are identified and are in concentrations that would adversely effect the calculated ethanol result, the analysis can be aborted.

One other important point is that the differing concentrations of alcohol or other energy absorbing compounds found in the subject's breath sample are not in a one to one relationship with the amount of energy that reaches the detector. In other words, a .050 alcohol concentration may absorb X units of infrared energy, but a .200 will not absorb 4X units of infrared energy. This inherent non-linearity can be overcome by performing a multi-point calibration. To ensure that the instrument is properly quantifying alcohol and the other substances, it would be prudent to perform multi-point accuracy checks for each substance of interest and ensure proper calibration over the entire range of substances and concentrations.

Finally, infrared systems require power to light the IR source, heat the sample chamber, power the light modulator and drive the detector and associated circuits. Historically, the signal from the detector has been small relative to the noise generated in the system. This has made it difficult to resolve changes in the signal when low level concentrations of alcohol are presented to the system. To solve this problem, several manufacturers have included cooled detectors. These systems require additional power, but the cooled detector decreases the noise on the detector and enhances the instrument's performance at the low alcohol