Real-Time Monitoring of Gas-Phase and Dissolved CO₂ Using a Mixed-Matrix Composite Integrated Fiber Optic Sensor for Carbon Storage Application

Abstract

Novel chemical sensors that improve detection and quantification of CO 2 are critical to ensuring safe and cost-effective monitoring of carbon storage sites. Fiber optic (FO)-based chemical sensor systems are promising field-deployable systems for real-time monitoring of CO 2 in geological formations for longrange distributed sensing. In this work, a mixed-matrix composite integrated FO sensor system was developed with a purely optical readout that reliably operates as a detector for gas-phase and dissolved CO 2 . A mixed-matrix composite sensor coating consisting of plasmonic nanocrystals and hydrophobic zeolite embedded in a polymer matrix was integrated on the FO sensor. The mixed-matrix composite FO sensor showed excellent reversibility/stability in a high humidity environment and sensitivity to gas-phase CO 2 over a large concentration range. This remarkable sensing performance was enabled by using plasmonic nanocrystals to significantly enhance the sensitivity and a hydrophobic zeolite to effectively mitigate interference from water vapor. The sensor exhibited the ability to sense CO 2 in the presence of other geologically relevant gases, which is of importance for applications in geological formations. A prototype FO sensor configuration, which possesses a robust sensing capability for monitoring dissolved CO 2 in natural water, was demonstrated. Reproducibility was confirmed over many cycles, both in a laboratory setting and in the field. More importantly, we demonstrated on-line monitoring capabilities with a wireless telemetry system, which transferred the data from the field to a website. The combination of outstanding CO 2 sensing properties and facile coating processability makes this mixed-matrix composite FO sensor a good candidate for practical carbon storage applications.

Multi-parametric gas sensing for transformer monitoring using an optical fiber sensor array

“…The sensor probe consists of three distinct evanescent field optical fiber sensors with different sensing materials targeted to different gas species. A first was coated with a "polymer of intrinsic microporosity" (PIM-1) incorporated with indium tin oxide (ITO) nanocrystals, similar to those described in [15][16][17]. This sensing material was deposited on optical fiber etched to remove the cladding layer (Thorlabs FG105LCA, etched to approximately 95 µm).…”

“…The three sensors were installed in a perforated stainless-steel tube, protected by porous polytetrafluoroethylene (PTFE) tubing (International Polymer Engineering; 0.011" wall thickness, 1.10 g/cm 3 ), to provide a gas permeable package for deployment in mineral oil, as previously demonstrated in water [17]. The sensor probe was installed in a sealed quartz tube for testing under flowing controllable gas mixtures (Fig.…”

Plasmonic and interferometric optical fiber sensors for electrical system monitoring applications

“…Combining a discrete number of engineered sensing layers in a single sensor probe as recently described in our prior work [30], also allows for investigation and analysis of numerous independent analytes simultaneously with a single sensor. A common method for analyzing responses of "photonic nose" technologies is principal component analysis, in which large data sets containing measurements of individual wavelengths from one or more functionalized sensor layers are reduced in dimension while still retaining most of the unique information contained within about a complex gas mixture [48].…”

“…5a). The setup seals the multi-fiber probe (containing previously tested Ni/SiO2, AuPd, and PIM-1/ITO sensors) within a stainless-steel tube, perforated with small holes and jacketed with oil-resistant, but gas-permeable PTFE tubing [48]. The probe is then sealed inside a quartz tube with two plastic tubes, one on each end, to allow for oil samples to be injected in one end and expelled on the other.…”