Hydrogen Sulfide Gas Detection via Multivariate Optical Computing

Abstract

Hydrogen-sulfide gas is a toxic, colorless gas with a pungent odor that occurs naturally as a decomposition by-product. It is critical to monitor the concentration of hydrogen sulfide. Multivariate optical computing (MOC) is a method that can monitor analytes while minimizing responses to interferences. MOC is a technique by which an analogue calculation is performed entirely in the optical domain, which simplifies instrument design, prevents the drift of a calibration, and increases the strength and durability of spectroscopic instrumentation against physical perturbation when used for chemical detection and identification. This paper discusses the detection of hydrogen-sulfide gas in the ultraviolet (UV) spectral region in the presence of interfering gaseous species. A laboratory spectroscopic measurement system was set up to acquire the UV spectra of H2S and interference gas mixtures in high-pressure/high-temperature (HPHT) conditions. These spectra were used to guide the design and fabrication of a multivariate optical element (MOE), which has an expected measurement relative accuracy of 3.3% for H2S, with a concentration in the range of 0–150 nmol/mL. An MOC validation system with the MOE was used to test three samples of H2S and mercaptans mixtures under various pressures, and the relative accuracy of H2S measurement was determined to be 8.05%.

Multigas Sensing Technique Based on Quartz Crystal Tuning Fork-Enhanced Laser Spectroscopy

“…Methane (CH 4 ) and carbon dioxide (CO 2 ) are two important greenhouse gases that play an important role in climate change and global warming. , Hydrogen sulfide (H 2 S) is a colorless, flammable, explosive, and highly toxic natural gas component. − H 2 O is an important molecule with high content in atmospheric components. Therefore, CH 4 , CO 2 , H 2 S, and H 2 O were initially selected as the target species to demonstrate the reported sensor technique due to their important influence in the atmospheric environment.…”

A New Multivariate Optical Computing Microelement and Miniature Sensor for Spectroscopic Chemical Sensing in Harsh Environments: Design, Fabrication, and Testing

“…One suitable candidate technique for downhole fluid identification in harsh oil and gas environments is multivariate optical computing (MOC). MOC is a compressed sensing technique used to extract compositional information from a straightforward broadband optical transmission measurement [8,9]. A typical oil and gas optical spectrum consists of a multitude of interfering absorption peaks characteristic of all the chemical species present.…”