The primary areas to look at are the type of oven and shelter you select
Oven Options New technologies in airless ovens offer a more flexible, cost-saving choice over traditional air-bath ovens. The airless oven enables the GCs to perform well in environments with changing temperatures. Air-bath ovens rely on plant or compressed air to heat the analytical oven to a constant and optimal temperature – which means a temperature above the dewpoint and optimized for component separation. Airless ovens don’t require expensive air sources, and consequently, consume less power. This means that the GC can be mounted closer to the sample point, reducing sample line run lengths, and ultimately, saving money, reducing the volume of sample required, and in installations requiring heated lines, reducing utility requirements. In fact, an airless oven can reduce overall operating costs by up to 70 percent. In addition, they take up less space than air baths. Reduced space and energy requirements make them well suited for a number of process applications.
Shelter Options There are three choices – analyzer house, a three-sided shelter or sunshield, and a field-mounted gas chromatograph with no shelter.
Analyzer House — An analyzer house is ideal for plants in extremely hot or cold climates and where the safety and comfort of the employees is a key consideration. Complete analyzer houses are also the most costly option, however. In addition to an expensive enclosed structure, there are significant hidden costs associated with an analyzer house, including high shipping fees, extensive cabling and tray requirements, increased assembly and installation costs, high maintenance fees, more required spare parts, and high utility and power consumption. Because an analyzer house can potentially entrap hazardous gases, additional capital expenses, including hazardous area compliance, safety systems, and fire and gas detection systems are often required.
Three-sided shelters or sunshields — Because they are designed with an open structure, three-sided shelters and sunshields have no risk of entrapment of hazardous gases, and as such, offer a lower cost solution by not requiring HVAC equipment, a safety system, or fire and gas detection systems. Also, shipping expenses are significantly less because a three-sided shelter weighs considerably less than an analyzer house. There will still be capital expenses associated with cabling and trays, assembly and installation, and maintenance and spare parts, but it will be lower than the capital expenses associated with an analyzer house.
Field-mounted solution (no shelter) — Field-mounted gas chromatographs that offer a flameproof and weatherproof enclosure provide the greatest overall savings. There are no shelter-related expenses, in most cases, the only cabling that is required is the cabling that comes with the gas chromatograph, and shipping expenses are very low.
I read about the 700XA on the Emerson website. Can you confirm that the 700XA can run ISO butane, normal butane application in 5-6 minutes?
In reply to Gopi KK:
What about when there are big temperature swings?
Does the Emerson GC have dual detector capabilities such as TCD, FID?
The current Emerson GC's are designed to handle a mix of detectors. it can be configured to run with dual TCD , TCD/FID andwith an extrenal detector module can run FPD for sulfurs.
In reply to Matt Scanlon:
Matt I assume you are reffring to the last item on the subject of Toptotal cost of ownwer ship. NO SHELTER
No anlsyser can be mounted in direct sunlight without some long term effects. First point is that direct sunlight could raise skin temperatures that could cook eggs. No shelters ....you need at least sun shade , if not some rain protection for any techniucain that may want to work onthe unit.
Just a remineder the ambient specification -20 to 60 deg C ......direct sunlight could well exceed the tempertaure limits.
Does an airless GC provide the same reliable and repeatable analysis results as a traditional airbath GC?Also, Why does a 3 sided shelter have a lower installation and operational cost?
Gopi - if you could provide a little more information about the application, I can answer your question. What other components are present in the sample stream - Methane, Propane, Carbon Dioxide, etc.? Also, what are the concentrations of those components, as welll as the concentration of Normal and Iso-Butane? Our 770XA standard C6+ GC can analyze the requested butanes in as little as 3 minutes, but this is again, based on the measured range (0-5% for each of the Butanes) and the remaining components and their concentrations in the sample gas.
In reply to V_Ansabaru:
Great Questions!
1) Of course! Designers of airless GCs understand that the performance of the GC cannot be compromised in order to save on installation and operational costs. As such, they design their GCs to perform as well or better than the traditional airbath GCs. Additionally, most GC analysis are performed at temperatures well above ambient (80-100 degrees C), so there is never a need to cool the oven.
2) The 3-sided shelter does not require a heater and air conditioner, and there is no need for a purge. Because there is no confined space concerns, the end user typically will not need a safety monitor of any type. Eliminating these items significantly reduces both installation and operational costs. No plant air, no power for the heater and air conditioner, no replacement of safety monitors and sensors, etc.
Another great source of information regarding the advantages of field mountable gas chromatographs can be found at our www.rosemountanalytical.com website, or by cutting and pasting the following into your web browser.
www2.emersonprocess.com/.../GC_Article_HydroCarbonProcessing_Oct2011_20120119.pdf