Development of a 1 x N Fiber Optic Sensor Array for Carbon Sequestration Site Monitoring

Repasky, Kevin¹ 

[1]Montana State Univ., Bozeman, MT (United States)

DOI  :  10.2172/1123881
RP-ID  :  None
PID  :  OSTI ID: 1123881

美国|英语

来源: SciTech Connect

【 摘 要 】

A fiber sensor array for sub-surface CO₂ concentrations measurements was developed for monitoring geologic carbon sequestration sites. The fiber sensor array uses a single temperature tunable distributed feedback (DFB) laser operating with a nominal wavelength of 2.004 ??m. Light from this DFB laser is direct to one of the 4 probes via an in-line 1 x 4 fiber optic switch. Each of the 4 probes are buried and allow the sub-surface CO₂ to enter the probe through Millipore filters that allow the soil gas to enter the probe but keeps out the soil and water. Light from the DFB laser interacts with the CO₂ before it is directed back through the in-line fiber optic switch. The DFB laser is tuned across two CO₂} absorption features where a transmission measurement is made allowing the CO₂ concentration to be retrieved. The fiber optic switch then directs the light to the next probe where this process is repeated allowing sub-surface CO₂ concentration measurements at each of the probes to be made as a function of time. The fiber sensor array was deployed for fifty-eight days beginning June 19, 2012 at the Zero Emission Research Technology (ZERT) field site where sub-surface CO₂ concentrations were monitored. Background measurements indicate the fiber sensor array can monitor background levels as low as 1,000 parts per million (ppm). A thirty four day sub-surface release of 0.15 tones CO₂/day began on July 10, 2012. The elevated subsurface CO₂ concentration was easily detected by each of the four probes with values ranging to over 60,000 ppm, a factor of greater than 6 higher than background measurements. The fiber sensor array was also deploy at the Big Sky Carbon Sequestration Partnership (BSCSP) site in north-central Montana between July 9th and August 7th, 2013 where background measurements were made in a remote sequestration site with minimal infrastructure. The project provided opportunities for two graduate students to participate in research directly related to geologic carbon sequestration. Furthermore, commercialization of the technology developed is being pursued with five different companies via the Department of energy SBIR/STTR program