XOS Sindie Online Single-Wavelength Wavelength-Dispersive X-ray Fluorescence (WDXRF) Online Total Sulfur Analyzer

Overview

The XOS Sindie Online is an industrial-grade, fixed-mount online total sulfur analyzer engineered for continuous, real-time sulfur quantification in liquid petroleum streams—including gasoline, diesel, naphtha, and light distillates. It employs single-wavelength wavelength-dispersive X-ray fluorescence (MWD-XRF), a physics-based analytical technique that isolates monochromatic primary excitation at the sulfur K-absorption edge (~5.37 keV) using dual hyperbolic curved crystal optics. This selective excitation minimizes spectral background and matrix interference, enabling high signal-to-noise ratio detection without chemical digestion, thermal decomposition, or carrier gas consumption. Unlike energy-dispersive (EDXRF) or combustion-based methods, the Sindie Online operates at ambient temperature and pressure, eliminating sample phase change, consumables, and associated calibration drift. Its design targets compliance with regulatory sulfur control mandates—including Euro 6, Tier 3, and IMO 2020—by delivering trace-level accuracy directly in process lines.

Key Features

• Monochromatic WDXRF architecture with dual hyperbolic bent-crystal optics for precise sulfur Kα (0.5373 nm) isolation and background suppression
• Sub-ppm detection capability: LOD of 0.5 ppm (as per ASTM D7039 validation protocols)
• Linear dynamic range spanning 0.6 ppm to 3000 ppm; extended range up to 10 wt% available via optical path reconfiguration
• No moving parts within the analyzer core—enhancing long-term reliability and reducing mean time between failures (MTBF)
• Self-contained flow cell with dynamic window technology ensuring consistent beam-sample interaction and thermal stability
• Flexible mounting options: floor-standing or wall-mounted configurations compliant with NEMA 4X and IP65 enclosures
• ATEX II 2G Ex db IIB T4 Gb / NEC Class I, Division 2, Group B, C, D certified variants available for hazardous area deployment
• Single-point calibration sufficiency across full range for representative hydrocarbon matrices (e.g., diesel, reformate, hydrotreated naphtha)

Sample Compatibility & Compliance

The Sindie Online is validated for direct analysis of transparent, low-viscosity liquid hydrocarbons with minimal particulate content (<5 µm filtration recommended). It accommodates flowing stream conditions typical of pipeline transfer, tank farm interfaces, and hydrotreater product lines (operating pressures up to 10 bar, temperatures from 10–60 °C). Method equivalence is formally established against ASTM D7039–15, NB/SH/T 0842–2017, and ISO 20884–2019. Instrument firmware and data handling workflows support audit-ready operation under GLP and refinery-specific QA/QC frameworks. Optional 21 CFR Part 11-compliant software modules provide electronic signatures, audit trails, and role-based access control for regulated environments.

Software & Data Management

The embedded Linux-based control system runs XOS ProcessLink™ firmware, supporting Modbus TCP, OPC UA, and analog 4–20 mA output for seamless integration into DCS and MES platforms. Real-time concentration values, measurement timestamps, diagnostic flags (e.g., flow interruption, window contamination alert), and raw spectral counts are logged locally with configurable retention (≥30 days). Remote diagnostics and firmware updates are performed over secure SSH or TLS-enabled web interface. Historical datasets export in CSV or ASTM E1399-compliant format for trending, SPC charting, and reconciliation with lab reference data (e.g., ASTM D2622 or D5453).

Applications

• Refinery process monitoring: Real-time feedback for hydrotreater severity control and feed/product sulfur balancing
• Product blending optimization: Detection of low-sulfur/high-sulfur interface during tank switching or pipeline batch transfer
• Terminal quality assurance: Automated pass/fail screening prior to custody transfer or marine fuel loading
• Regulatory compliance verification: Continuous reporting for EPA, CARB, or EU Fuel Quality Directive (FQD) reporting requirements
• Crude assay correlation: Supporting sulfur allocation models when deployed upstream of desalters or atmospheric units

FAQ

Does the Sindie Online require carrier gas or consumables during operation?

No. The MWD-XRF method is entirely gas-free and requires no reagents, filaments, or sacrificial components.
Can it analyze viscous or opaque samples such as heavy fuel oil or residuum?

No. It is optimized for clear, low-viscosity distillates. Heavy fractions require dilution or alternative methods (e.g., ASTM D2622).
How frequently must calibration be performed?

Typically once per quarter for stable process streams; frequency may extend to semi-annual under controlled, low-drift conditions with routine blank verification.
Is the analyzer compatible with explosion-proof zones in refineries?

Yes—certified variants meet ATEX Zone 1/21 and NEC Class I Div 2 requirements; installation must follow local electrical classification guidelines.
What sample conditioning is required upstream?

A 5-µm particulate filter, pressure regulator (if line pressure exceeds 10 bar), and temperature stabilization loop (±2 °C) are recommended for optimal performance.