Carbon dioxide sequestration monitoring and verification via laser based detection system in the 2 micron band

Abstract

Carbon Dioxide (CO 2) is a known contributor to the green house gas effect. Emissions of CO 2 are rising as the global demand for inexpensive energy is placated through the consumption and combustion of fossil fuels. Carbon capture and sequestration (CCS) may provide a method to prevent CO 2 from being exhausted to the atmosphere. The carbon may be captured after fossil fuel combustion in a power plant and then stored in a long term facility such as a deep geologic feature. The ability to verify the integrity of carbon storage at a location is key to the success of all CCS projects. A laser-based instrument has been built and tested at Montana State University (MSU) to measure CO 2 concentrations above a carbon storage location. The CO 2 Detection by Differential Absorption (CODDA) Instrument uses a temperature-tunable distributed feedback (DFB) laser diode that is capable of accessing a spectral region, 2.0027 to 2.0042 microns, that contains three CO 2 absorption lines and a water vapor absorption line. This instrument laser is aimed over an open-air, two-way path of about 100 m, allowing measurements of CO 2 concentrations to be made directly above a carbon dioxide release test site. The performance of the instrument for carbon sequestration site monitoring is studied using a newly developed CO 2 controlled release facility. The field and CO 2 releases are managed by the Zero Emissions Research Technology (ZERT) group at MSU. Two test injections were carried out through vertical wells simulating seepage up well paths. Three test injections were done as CO 2 escaped up through a slotted horizontal pipe simulating seepage up through geologic fault zones. The results from these 5 separate controlled release experiments over the course of three summers show that the CODDA Instrument is clearly capable of verifying the integrity of full-scale CO 2 storage operations.