System for the analysis of hydrogen sulfide and mercaptans in crude oil
The industrial system for the analysis of hydrogen sulfide and mercaptans in crude oil—developed by NTF "BAKS"—is a specialized measurement solution designed for continuous, in-line monitoring of the mass concentration of hydrogen sulfide (H2S) and light thiols (methyl mercaptan, CH3SH, and ethyl mercaptan, C2H5SH) in crude and commercial oil. The system enables real-time assessment of volatile sulfur-containing compounds directly within the technological process. This entirely eliminates the need for manual sampling of hazardous materials and their subsequent transport to a laboratory, while also reducing the risk of inaccurate results caused by a loss of system containment.
Innovative Operating Principle and System Components
The system is built upon a robust configuration of equipment, all certified with an EExdIICT4 explosion-proof rating:
A sampling system featuring a patented vapor-phase sampler: oil flows continuously through a sample preparation unit. Within this unique sampler—which has no global equivalent and contains no moving parts—thermodynamic equilibrium is established between the liquid (oil) and gas (vapor) phases. A predictable portion of the H2S and mercaptans migrates into the vapor phase.
An industrial gas chromatograph ("MAG"): the vapor phase is automatically injected into the chromatograph’s capillary column, where the components are separated with high resolution.
A highly linear electrochemical detector (ECD): this component measures the precise concentrations of the separated gases. Using established distribution coefficients, the software instantly recalculates the data to provide the actual concentration of sulfur compounds present in the liquid oil. Key Operational Advantages
Savings on consumables: Ordinary filtered air is used as the carrier gas for the chromatograph, eliminating the need to purchase cylinders of expensive, high-purity inert gases.
High speed: A complete measurement and data update cycle takes less than 10 minutes.
Wide measurement range: 0.5 to 300 ppm for H2S; 2 to 300 ppm for methyl and ethyl mercaptans, with stable repeatability of results ranging from 3% to 6%.
Minimal maintenance: The system performs automatic calibration using a single reference gas mixture, and the absence of moving parts in the vaporization unit ensures the longevity of the system.
Easy integration: Data transmission to the facility’s automated process control system (APCS) is supported via RS-485 and RS-232 interfaces using Modbus RTU/TCP protocols.
Analyzed components: Hydrogen sulfide, ethyl mercaptan, methyl mercaptan
Detector type: Electrochemical detector (ECD)
Column type: Capillary
Measurement range:
H2S: 0.5 – 300 ppm
CH3SH, C2H5SH: 2 – 300 ppm
Repeatability: 3% to 6% (at low concentrations)
Analysis time: Less than 10 minutes
Explosion protection: EEx d II C T4
Interface: RS-485, RS-232, Modbus RTU/TCP
