Simple, Precise, and Reliable On-Line Sulfur Analysis

XOS (USA) has been at the forefront of elemental analysis of petroleum products for well over a decade, supplying tools like the Sindie® Sulfur Analyzer to aid with the ultra-low-sulfur-diesel (ULSD) implementation in the early 2000s as well as the California Air Resources Board (CARB) requirements for gasoline.  With sulfur limits dropping lower and lower due to global regulations, it is critical to seek out the most efficient and precise process technologies for measuring sulfur at these ultra-low levels.

Cutting Through the Noise

Although X-ray fluorescence (XRF) technology has been a standard in the petroleum business for many years, the introduction of XOS-patented monochromatic wavelength dispersive X-ray fluorescence (MWD XRF) technology has surpassed the traditional limits of XRF sulfur analysis. MWD XRF, a simplified and highly robust X-ray technique, provides sub-1 ppm sulfur detection.  This improved performance has allowed us to deliver not only in the lab but also on the process where the SINDIE On-Line analyzer offers a great number of benefits over other technologies currently being used for this application.

An MWD XRF analyzer engine (Figure 1) consists of a low-power X-ray tube, a point-to-point focusing optic for excitation, a sample cell, a second focusing optic for collection and an X-ray detector. The first focusing optic captures a narrow bandwidth of X-rays from the source and focuses this intense monochromatic beam to a small spot on the fuel cell. The monochromatic primary beam excites the sample and secondary characteristic fluorescence X-rays are emitted. The second collection optic collects only the characteristic sulfur X-rays that are then focused onto the detector.  The analyzer engine has no moving parts and does not require consumable gasses or high temperature operations. 

MWD XRF eliminates the scattered background peak caused by the x-ray tube and improves the signal-to-background ratio (S/B) by a factor of 10 compared to conventional WD XRF.  The S/B is improved by using the monochromatic excitation of the x-ray source characteristic line. Additionally, the focusing ability of the collection crystal allows for a small-area x-ray counter, which results in low detector noise and enhanced reliability.

Automating Your Process to Save Time and Money

At the refinery, improved repeatability (Figure 2) can have a major impact on the process. The ability to closely monitor and immediately identify process shifts of 1-2 ppm sulfur can result in extended catalyst life and reduced costs. With sulfur regulations such as Tier 3 in and Euro V pushing the levels to 10ppm and below, precision becomes even more critical.  In a pipeline application, MWD XRF technology also helps to ensure consistent, reproducible results as products pass from site to site. It is also critical at pipeline terminals to monitor interface cuts and tank contamination prevention. Manual sampling takes too long and results in deep interface cuts plus significant downgrading.  Interface cuts (to separate fuel batches) should be done based on real-time monitoring of sulfur content—measurement times of 30 seconds or less—to avoid wasting material.   The precision of the Sindie On-Line system, powered by MWD XRF, enables automation of the closed loop process control, which saves money and resources. 

The Sindie On-Line Analyzer uses a cutting edge dynamic window module (DWM) to continuously monitor sample as it would flow through the process.  This allows for quick, low maintenance analysis of many different types of petroleum products from crude oil to gasoline. There are no costly maintenance items, such as high temperature combustion furnaces, and no consumable gasses needed for measurement. 

The Sindie On-Line can perform in the toughest of environments around the world. We know that uptime is critical in the petroleum industry.  The SINDIE On-Line’s robust and rugged design allows you to be confident that your instrument will be running at peak performance 24 hours a day, 7 days a week.   

Additional features include:

Direct measurement without sample conversion;
Analysis in ppm (wt)    (Figure 3)
Dynamic Range: 0.6 to 3000 ppm
Outstanding linearity: One calibration for diesel and gasoline matrixes over full dynamic range
[Text Box: Figure 3: On-line monitoring of diesel at various sulfur levels] Fast measurement time: 30 seconds to 5 minutes, user programmable

From terminals to mobile labs to refineries, XOS is a leader in the field of elemental analysis.

Contact XOS to discuss your testing needs and learn more about the XOS line of portable, lab, and process analyzers for either single or multi-element detection, delivering unrivaled precision at the push of a button.  XOS field experts can be reached at info@xos.com or by calling 1-518-880-1501.