Distributed Sensors for Dissolved Carbon Dioxide
Small Business Information
2520 W. 237th Street, Torrance, CA, -
AbstractThe storage of industrially generated carbon dioxide in deep geologic formations is being seriously evaluated as a method for reducing carbon dioxide emissions to the atmosphere. Reliable and cost-effective monitoring is required to demonstrate that geologic storage is safe and effective for controlling carbon dioxide emissions. Carbon dioxide leaking from a deep storage reservoir is likely to intercept groundwater resources. Two characteristics differentiate water monitoring from other monitoring techniques: subsurface water forms an integrating horizon that covers a large area above the gas reservoir, and the direct monitoring of water protects our most important natural resource. However, current methods for groundwater monitoring, based on sampling followed by laboratory analysis, are far too costly and labor-intensive for the long-term monitoring of large areas. This effort will result in the development of the world & apos;s first truly distributed dissolved carbon dioxide sensors, and will help to overcome current limitations. The sensors, which will be based on optical fibers manufactured so that their entire lengths are coated with doped polymers, will allow the spatially averaged or position-resolved detection of carbon dioxide during and after geological sequestration. This stand-alone system will monitor continuously for leaks, but more importantly, will quantify the amount of the carbon dioxide leaked into aquifers, key information required to begin remediation. Work in Phase I demonstrated the feasibility of preparing distributed fiber carbon dioxide optic sensors by coating segments of optical fibers with novel solid-phase sensitive materials, and interrogating the fluorescent coating through the evanescent wave field. The prototype sensors were evaluated for their analytical features, showing excellent features for the long-term monitoring of carbon dioxide in carbon sequestration. The overall objective is to build a fiber optic sensor system for fully-distributed carbon dioxide monitoring, and validate its performance in field tests at carbon sequestration pilot sites. Carbon-dioxidesensitive fibers will be fabricated using commercial manufacturing techniques. Sensor cables will be assembled, and a read-out unit will be developed. The system will be fully characterized in the laboratory under simulated underground conditions, and the results will be compared with field test data. Commercial Applications and Other Benefits: Carbon capture and sequestration may ultimately contribute to up to 20 percent of carbon dioxide-emission reductions over the coming century. Worldwide, annual carbon dioxide emissions from human activity are accounted to be more than 33 billion tons. Over 60 percent of the carbon dioxide emissions come from sources that are potentially amenable to carbon dioxide capture. Estimated costs for monitoring geologic storage over the full life-cycle of a project range up to $0.10 per ton of carbon dioxide, which provides a vision of the important market opportunity for monitoring techniques.
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