Online Sulphur Measurement by X-ray Transmission Enables Compliance with New Marine Fuel Regulations

Aug 18 2020

Online, real time X-ray Transmission (XRT) measurement of sulphur (S) in heavy or light oils is used to satisfy the needs of refineries, pipelines, blending operations, bunkering terminals and other storage facilities.

Applications include bunker fuel blending to meet MARPOL Annex VI sulphur restrictions, interface detection of different grade fuels delivered via pipelines, refinery feedstock blending and monitoring, diesel/kerosene blending or production, and the quality monitoring of crude at remote collection and storage facilities.

Regulations limiting the sulphur content of fuel used in the marine industry continues to evolve, resulting in ever-tightening regulations restricting sulphur (S) emissions from ships’ fuel. As of January 2020, IMO (International Maritime Organisation) guidelines set the maximum allowable sulphur content of marine bunker fuel at sea at 0.5 wt% - a further reduction from the 1.0 wt% limit established in 2015.

Online, real time X-ray transmission is an established method for the measurement of sulphur in heavy and light hydrocarbon process streams and a valuable tool for monitoring sulphur levels in relation to the latest regulations.

While in-line sulphur gauging for blending, switching and QC has been around for years, older technologies never delivered on their promise because those systems did not produce consistent measurements. X-ray transmission gauging involves measuring the attenuation of a monochromatic X-ray beam transmitted through the oil. In practice, a process stream passes through a flow cell where sulphur in the hydrocarbon matrix absorbs X-rays transmitted between an X-ray source and detector. The recorded X-ray intensity is negatively correlated to the sulphur concentration, thus the highest sulphur levels transmit the least X-rays.

For the accurate online determination of sulphur, the Rigaku NEX XT X-ray transmission (XRT/XRA) process sulphur gauge resolves past issues, making it the ideal tool for blending operations supplying marine bunker fuels and crude feedstock for refineries.

With uniquely engineered hardware and novel proprietary software technologies, the NEX XT analyser is faster, more sensitive and far more compact than previous generation systems, and provides continuous, reliable detection of sulphur from 200 parts-per-million (ppm) to 6.0 wt. %, with analysis times as short as 1 second. The NEX XT system can operate as a stand-alone analyser or provide real time closed loop control when tied into a blending or plant wide automation system.

Simple, intuitive software interface makes calibration and analysis easy. Calibrate once, and then continuous sulphur results are reported automatically as oil flows through the analysis chamber. The update frequency is user configurable. The system is designed for unattended operation and requires no consumables or routine maintenance. Grab samples can be occasionally taken for verification testing using another technique, such as the Rigaku NEX QC EDXRF benchtop analyser for ASTM D4294 compliance.

Whether used for crude oil blending and monitoring, assaying, blending marine bunker fuels or switching pipelines, the Rigaku NEX XT XRT process analyser is well suited to meet the varying demands of the industry.

Marine bunker fuel