Progress 07/01/23 to 10/31/24
Outputs
Target Audience: The intended audience for this effort is all stakeholders in the detection, quantification and reduction for anthropogenic fugitive methane emissions. Those include but are not limited to: • Livestock farmers • Landfill operators • Legislators • Government agencies concerned with development, administration and enforcement of air quality standards. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The major activities and experiments conducted in the project were: Initial Testing of PBS Methane System: The PBS system was characterized against a controlled black body source in the laboratory to determine its response to an object at a known temperature. It was then tested outdoors against a cold sky background to assess its behavior under real-world conditions. Methane Cloud Concentration Calculations: Calculations were performed using Beer's Law to determine the concentration of methane needed in the gas cell to mimic realistic methane releases from agricultural sites. Calibration Curve Generation: A working curve of methane absorbance peak area versus concentration in the IR optical cell was generated using FTIR measurements. This was done to evaluate the PBS system's capabilities for methane discrimination and quantification. Additional Filter Selection: New filter sets were selected to improve the discrimination and sampling of the methane bending absorption band. These filters were chosen based on their ability to break symmetry and sample more of the sharp, narrow peak in the methane absorption band. These activities and experiments were crucial in demonstrating the PBS system's potential for methane detection and quantification, and in informing the selection of optimal filter sets for future testing. The data collected from the experiments included: RMS Signal Measurements: The RMS signal for each channel of the PBS system was measured under different conditions: While "looking" at a blackbody source at 0°C in the laboratory. While viewing a clear sky with no clouds. While viewing a clear sky with an empty gas cell present. CIE-IR Coordinates: The CIE-IR X, Y, and Z coordinates were calculated from the PBS system measurements for different concentrations of methane injected into the gas cell. FTIR Transmission Spectra: Transmission IR spectra were collected using an FTIR spectrometer for all samples, including the blank and methane-filled gas cell. Peak Area of Absorbance: The peak area of absorbance for the C-H bending band of methane was measured at different concentrations using the FTIR. These data were used to evaluate the PBS system's performance, to determine the necessary methane concentration in the gas cell for realistic simulations, and to establish a relationship between the CIE-IR coordinates and methane concentration Summary Statistics and Discussion of Results Initial PBS System Testing: The PBS system demonstrated stable RMS signal measurements with low relative standard deviations (RSDs) when measuring both a controlled blackbody source and a clear sky background. This indicates consistent and reliable performance. The presence of an empty gas cell did not introduce significant variations in the RMS signal. Methane Concentration Calculations: Calculations based on Beer's Law and real-world methane cloud data determined that a methane concentration of 25,500 ppm in the gas cell was necessary to accurately mimic realistic methane releases from agricultural sites. Calibration Curve Generation: FTIR measurements were used to generate a working curve of methane absorbance peak area versus concentration. The C-H bending absorption band at 1300 cm-1 exhibited a larger peak area than the C-H stretching band, suggesting better discrimination potential. The linear relationship between peak area and concentration confirmed adherence to Beer's Law. Additional Filter Selection: Initial filter sets did not effectively capture the sharp, narrow peak of the methane absorption band. New filter sets were selected to improve discrimination and sampling of this peak, enhancing the system's sensitivity and selectivity. CIE-IR Coordinate Analysis: The calculated CIE-IR coordinates showed a strong dependence on methane concentration offering a potential method for quantifying methane levels using the PBS system. Future Work: The promising results obtained led to the purchase of new filter sets for further testing and optimization. Future work will involve constructing multiple PBS systems with these filters and conducting field tests in relevant environments to verify the system's capabilities for real-world methane detection and quantification. Overall, the results of the study demonstrate the potential of the PBS system as a viable technology for the detection and quantification of methane emissions from agricultural sites. The system's stability, sensitivity, and selectivity were validated through laboratory and field experiments. The analysis of the dependence between CIE-IR coordinates and methane concentration provides a promising pathway for future quantification efforts. Further testing and optimization with the new filter sets are expected to enhance the system's performance and pave the way for its practical application in monitoring and mitigating methane emissions. The key outcomes and accomplishments realized from the project include: Successful demonstration of the CIE analytical approach for discriminating methane from background chemicals. This was achieved through calculations based on gas vapor transmission spectra and filter spectra. Validation of Beer's Law for methane concentrations. FTIR measurements confirmed that the band areas of both the C-H bending and stretching bands of methane scale linearly with concentration, as predicted by Beer's Law. Selection of filter sets that show good discrimination of methane from background interferents. Multiple filter sets were evaluated, and those demonstrating optimal selectivity for methane were chosen. Establishment of a relationship between the measured signal and calculated CIE chromaticity coordinates on methane concentration. This relationship offers a potential method for quantifying the relative concentration of methane in air. Collection of valuable background data for future analysis. The initial testing of the PBS system against a controlled blackbody source and a clear sky background provided essential baseline data for future experiments and comparisons. These outcomes and accomplishments represent significant progress towards the development of a reliable and effective method for detecting and quantifying methane emissions using the PBS system.
Publications
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Progress 07/01/23 to 06/30/24
Outputs
Target Audience:The intended audience for this effort is all stakeholders in the detection, quantification and reduction for anthropogenic fugitive methane emissions. Those include but are not limited to: • Livestock farmers • Landfill operators • Legislators • Government agencies concerned with development, administration and enforcement of air quality standards ? Changes/Problems:A significant issue is that the commercially available, off the shelf optical filters are not in the best spectral position to provide for high selectivity for methane. To address this issue, we will order a set of custom infrared filters for mounting on the detector chip. This will provide us with the best capability to discriminate methane from background interferents based on recent calculations. What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?While calculations showed that the PBS would respond to the C-H bending absorption at 1300 cm -1 of methane in the atmosphere, we were not successful in generating a response to different concentrations of methane in an IR transmission cell against a cold sky background. Analysis of the spectral data from the FTIR suggest that the available IR filters do not fully interact with the C-H bending absorption band at ~1300 cm-1. The result of this is that changes in the C-H bending band were not observable by the PBS over the different concentrations of methane. To address this lack of signal response in the future custom filters, which exhibit greater overlap with the C-H bending band at 1300 cm-1, will be acquired. The system outfitted with custom filters will generate observable changes in the CIE-IR values from the system. An alternative approach will be to focus on the C-H stretching band at 3000 cm -1 which is a stronger band than the C-H bending band. Because the band is stronger we expect the PBS to be capable of detecting changes in the band area with respect to concentration.
Impacts
What was accomplished under these goals?
Aether will produce a novel, commercially viable technology for monitoring methane from livestock farms, manure management facilities, landfills, and gas and oil infrastructures. Our sensors will gather high-resolution air pollution data using a network of low-cost nodes for real-time detection of methane and iteratively be developed through the STTR program phases to incorporate methane concentration levels. This network will be able to cover a large area with minimal to no blind spots and serve as an intelligent decision support system, which can be embedded and automated through an application protocol interface or physically into partner technologies for methane remediation or capture. Principal beneficiaries of this effort fall in three categories: livestock operations, oil & gas industry, and landfill operations. There are many other possible commercial and governmental applications of this sensor technology. Methane is not only a recognized greenhouse gas but also the primary contributor to the formation of ground-level ozone, a hazardous air pollutant; exposure to which causes one million premature worldwide deaths every year. Livestock emissions from manure and gastroenteric releases account for approximately 36 percent of commercially produced methane emissions in the U.S. Further, methane leaks in the oil and gas industry in the U.S. result in approximately 13 million metric tons of methane released into the environment; this wasted gas is worth an estimated $2 billion, and to the point of this effort, severely impacts the Earth's climate. Also, landfills represent the third-highest source of methane globally. As one of the world's largest livestock, energy, and waste-producing countries, the U.S. requires practical tools for these vital industries to detect, measure, and reduce methane emissions. Standard chemical sensors, such as Fourier Transform Infrared Spectrometers (FTIR) are complicated to use, difficult to maintain, and very expensive. Alternatively, specialized imaging technology as part of satellites and aircrafts are ineffective because of their inability to continually monitor the thousands of potential methane sites for real time detection. Our solution is to provide the end user with a low cost, easy to operate system capable of monitoring methane emissions from various sites such as, but not limited to livestock farms, manure management facilities, landfills, and gas and oil infrastructures. Constant monitoring of these sites for methane emissions using our system will enable a low cost, efficient method to protect the environment and save lives by filling a gap in the chemical detection market. Aether's Industrial IoT system represents at least a 10X cost reduction over commercially available stand-off FTIR devices while retaining remote sensing capability and good chemical specificity. Aether's sensor system will enable wide adaptability as it will allow government agencies to enact climate change regulations in multiple industries that can be assessed and enforced. The modular design of our lightweight, portable, low cost sensors will empower livestock farmers, oil and gas companies, and landfill operators to afford a robust chemical vapor detection system to operate their enterprises responsibly and comply with local, state, and federal requirements. Major activities completed / experiments conducted; Progression of the development of the Passive Biomimetic Sensor (PBS) Data collected; Vapor transmission spectra and filter spectra. Calibration curve for methane detection / quantification CIE-IR tristimulus coordinates between methane, and the other relevant background chemical vapors. Working curve of C-H stretch band and C-H bend band for methane in air. Semi-quantification measurements for methane (ongoing). RMS signal for each channel of PBS when measuring the sky; no discontinuous trends observed. Summary statistics and discussion of results; Filter selection - Enhancement of methane optical detection via absorption band correspondence to CH bending and stretching modes; either band can be used to discriminate methane from background interference. Beer's law: Series of known concentration levels of methane can be generated in sample cells for discrimination Controlled and calibrated black body source to conduct 1000 measurements Discrimination of methane against cold sky background To date we have successfully demonstrated, via calculations, that the CIE analytical approach is capable of discriminating methane from background chemicals. In order to first demonstrate that the observed concentrations of methane were within the range that followed Beers law we acquired transmission measurements of varying concentrations of methane using the FTIR. Results from these measurements showed that the band area of the C-H bending band (1300 cm-1) and C-H stretching band (3000 cm-1) both scaled with concentration linearly as defined by Beers law. Looking at the operational aspect of the PBS we demonstrated that we could collect useful background data from the sky generating the response of the PBS to the sky with no analyte in the field of view of the sensor.
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