Transportable multi-parameter analytical instruments have been key to the growth of an analytical services company based in Elk City, Oklahoma. Great Plains Analytical Services (GAS) operates a fleet of mobile monitoring systems, providing onsite gas analysis for customers across the USA, and Gasmet FTIR analyzers have enabled the company to offer a comprehensive onsite monitoring service.
CEO Jordan Williamson says: “Our father started the business over 20 years ago employing portable test instruments to measure parameters such as VOCs, NOx, CO, CO2 and vibration. At that time, the monitoring technology was mostly basic electrochemical instruments and FID analysers. However, about seven years ago, facing increasing demands from the US Environmental Protection Agency, our customers demanded greater monitoring flexibility.
"The performance requirements for the analysers became tighter and a broader range of measurement parameters were required in many applications. As a result, we began to utilize Gasmet's FTIR technology and we are now running nine Gasmet DX4000 FTIR gas analyzers."
FTIR (Fourier Transform Infrared) spectroscopy detects gaseous compounds by measuring their absorbance of infrared radiation. Since different molecules have different atomic structures, each produces a unique infrared spectrum. Consequently, both qualitative and quantitative measurements are possible.
The Gasmet FTIR analysers are able to simultaneously measure multiple analytes in complex gas mixtures, detecting virtually all gas-phase species (both organic and inorganic). This is achieved by collecting a complete spectrum of the infrared light absorbed by molecules in the sample cell. Multiple spectra are acquired at 10 Hz rate and averaged together to improve sensitivity.
FTIR's multiparameter capability has been exploited by the instrument manufacturer Gasmet Technologies in a variety of instruments, which has meant that the technology can be employed in an enormous number of applications.
GAS customers' applications require measurements for parameters such as CO, NOx, moisture and a range of organic gases such as acetaldehyde, butane, ethylene, hexane, methane and propane, following test methods such as US EPA Test Method 320 and ASTM test method D6348.
Most of the applications handled by the monitoring teams at GAS involve the analysis of hot and often wet emissions. Consequently, the Gasmet DX4000 FTIR analyser is the most commonly deployed instrument. Rugged and lightweight, the DX4000 fits into the rear of the GAS monitoring trucks and with a heated sample cell and heated lines, accurate representative samples can be fed into the analyser without causing condensation. Typical applications for the GAS teams include natural gas, vapor recovery, and emissions monitoring of compression engines and combustion engines in the oil and gas sector and at other facilities such as hospitals and airports.
"Typically, we monitor for around 4 hours but this can extend up to 15 hours in some cases," Jordan says. "The prime objective is of course to demonstrate compliance with the appropriate regulations, however, our clients also use this opportunity to monitor engine performance and improve efficiency.
"In circumstances where an engine is not running efficiently, we sometimes see unexpected peaks in the recorded spectra. This can usually be quickly identified with an Advanced Library Search tool built into Gasmet's Calcmet professional software and by comparison with Gasmet's spectral library of thousands of compounds.
"The power of FTIR has clearly been instrumental in helping to meet the demands of our customers and drive growth in our business. However, it is important to recognise the help that we have had from Gasmet, both in the US and from Finland. Their staff have always provided prompt technical support whenever we needed it. For example, they even developed new features in the Calcmet software for us, such as the automatic calculation of Fractional Model Uncertainty and Minimum Analysis Uncertainty figures required by the test method EPA TM320. These complicated calculations were previously undertaken manually, so Gasmet has saved us a great deal of time by building them into the software."
Summarizing the benefits of Gasmet FTIR, Jordan says: "The small size of the Gasmet analyzers means that we are easily able to fit them into our fleet of trucks, avoiding the need for trailers. Also, by providing a wide range of measurements, we are able to help customers improve engine efficiency, whilst demonstrating emissions compliance. Importantly, the DX4000 is quick and easy to set up and run, which lowers our costs and means that we can deliver a fast, cost-effective service.”