I am Carolyn Snyder, business development manager for the process industry at Rosemount Analytical.
For many years, all process gas chromatographs were installed in shelters that usually cost significantly more than the analyzers themselves. From a technician’s point of view, a shelter was desirable for its climate control and comfort to troubleshoot and repair the analyzer. However, using a fully enclosed shelter requires several compromises. First, you give up proximity to the point of measurement, which means you spend more on cabling and sample tubing (often heated). Second, a shelter is limited in the number of units it can house. As your needs change, you may be required to invest in additional expensive shelters to accommodate the changes in your analytical scope. Because of these issues, most major suppliers of GCs have produced some form of a field-packaged unit that is theoretically capable of existing in a non-climate-controlled environment.
Which is why I was quite surprised to hear many of these suppliers still strongly advocate the use of conventional analyzers at the recent IFPAC conference held in Baltimore, Maryland. Sitting through several papers, I listened to presenters explain that only the simplest measurements can be made with field-mounted units. They also discussed some service-related issues centering on the expense of the modular concept, where the entire module is replaced rather than repaired in the field, which can be very costly.
What I’ve discovered over the past few months is that none of these issues apply to the field-mounted gas chromatographs manufactured by Emerson (sold as Rosemount Analytical into the process industry and Daniel Danalyzer into the natural gas industry).
First, the Emerson GCs all go through an environmental chamber to ensure there is no failure when temperatures vary from 0° to 130°F. They are designed with access to the various parts – electronics, boards, columns, detectors, etc. – so that repair in the field is feasible. Most importantly, these field-packaged analyzers are not restricted to simple applications. Some of the most strenuous measurements are easily performed by these units which house multiple valves, columns and detectors in addition to stream switching capability. The measurement of C9+ with HHV (higher heating value, or BTU) and HCDP (hydrocarbon dewpoint) has been provided in scores of field analyzer units to the satisfaction of many major hydrocarbon processing companies.
In short, performance does not have to be sacrificed in a field housing analyzer if it is properly designed and implemented.