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Measuring techniques and -principles

Measuring Techniques and -Principles for H2S and Total Sulfur

There are several principles for measuring H2S- and Total S-concentration in liquids and in gasses:

  • Colorimetric for H2S and Total Sulphur in combination with (catalytic) reduction,
  • (Pulsed) Ultra Violet Fluorescence ((P)UVF) in combination with oxidation of Sulfur components,
  • EDXRF (Energy Dispersive X-Ray Fluorescence),

 We supply above technologies as stand-alone analyzers or integrated into a complete solution.

 Measuring Principles:

 Colorimetric (H2S Analyzer): 

Features:

  • Interference free (selective to H2S only),
  • Detection limit < 1 ppb,
  • No zero drift,
  • 5 Seconds response on breakthrough,
  • Linear response,
  • Dual range capability,
  • Up to 4 channel analysis,
  • No other utilities than power supply required for ranges up to 100 ppm,
  • ATEX and CE certified.

This colorimetric method is available with (catalytic) reduction for gasses and liquids to measure Total Sulphur in liquids and gasses at low ppb and ppm levels. In combination with High Temperature Sampling and Injection, this method is suitable for wet gas applications such as amine scrubbers, separators, etc.

(Pulsed) Ultra Violet Fluorescence ((P)UVF) (Total Sulfur):

The Pulsed UVF method is based on oxidation of the Sulphur to SO2 at 1100 ºC, followed by UVF SO2 measurement. This method is suitable for gasses and liquids up to a Final Boiling Point (FBP) of 450 ºC.

Features:

  • Compliance to ASTM D5453, D2622 and ISO 20846 methods for Total Sulfur in petroleum products,
  • Measuring range from 0 to 5 to thousands of ppm,
  • Trace version for 0 to 2 ppm range,
  • Response time: 3 to 5 minutes for 90% of new value,
  • Comprehensive diagnostics,
  • Automatic control of UV light intensity  enables long term stability,
  • ATEX and CE certified.

EDXRF (Energy Dispersive X-Ray Fluorescence) (Total Sulfur):

The EDXRF method is measuring the Total Sulfur content in liquids without any conversion. It is a direct measurement of the Sulfur atom in any matrix.

The EXDRF method is especially suitable for liquid applications with a high final boiling point (FBP).

Features:

  • Concentration above 10 ppm to percent level [S],
  • True online analysis, measures average concentration over the measuring time,
  • No oxygen is required, requires only inert purge gas for explosion proof operation,
  • No matrix correction required,
  • For higher viscosities a heated sample cell is available,
  • No critical moving parts, minimum maintenance,
  • No high temperature components,
  • No consumabels,
  • The X-ray source is an X-ray tube; the radiation is stopped when the power is switched off,
  • ATEX classification, NEC purge available,
  • CE certified.

Other analytical methods:

In some cases our solutions require other analytical methods to meet your specific requirements.

Hobré Instruments has successfully supplied the Gas Chromatography method as well as the Tuneable Diode Laser method (TDL) in the oil and gas industry.

Gas Chromatography (GC) Method (H2S Analyzer):

The GC method is selected for specific sulphur components in gasses and liquids. H2S analysis in gasses in the range of 0 to 20 ppm and above is successfully done with the Yokogawa GC, model C1000 Mark II, using a Thermal Conductivity Detector (TCD) which eliminates the need for Hydrogen as utility gas. Cycle times of 3 minutes can be achieved of gasses with hydrocarbon and water dewpoints up to 80 ºC at 1 barg.

The GC-method is successfully applied for H2S and mercaptans in crude oil with the use of a stripping unit.

Tuneable Diode Laser (TDL-method) (H2S Analyzer):

This method employs a laser spectroscopy technique that measures trace amounts of H2S in gasses. The TDL method is an upcoming technology with low cost of ownership for the applications in the oil and gas industry.

Hobré Instruments has a partnership with a leading manufacturer in TDL technology.

The combination of TDL technology with our application experience offers a total solution with low cost of ownership; high reliability and fast response.

For specific applications, please consult us.