Thesis (M.E.S.)--York University, 2001. / Typescript. Includes bibliographical references (leaves 172-183). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ71712.

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains viii, 65 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 60-64).

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 62-77). Also available on the World Wide Web.

A novel approach to geologic CO₂ sequestration is the surface dissolution method. This method involves lifting native brine from an aquifer, dissolution of CO₂ into the brine using pressurized mixing and injection of the CO₂ saturated brine back into the aquifer. This approach has several advantages over the conventional approach, including minimization of the risk of buoyancy driven leakage and dramatic reduction in the extent of pressure elevation in the storage structure. The mass transfer coefficient for the CO₂/brine two-phase system and associated transport calculations allow efficient design of the surface equipment required to dissolve CO₂ under pressure. This data was not previously available in the literature. Original experimental data on the rate of dissolution of CO₂ into Na-Ca-Cl brines across a range of temperatures and wet CO₂ densities are presented. From this data, the intrinsic mass transfer coefficient between CO₂-rich and aqueous phases has been calculated. The statistically significant variation in the mass transfer coefficient was evaluated and compared with the variation caused by the experimental method. An empirical correlation was developed that demonstrates that the mass transfer coefficient is a function of the NaCl salinity, temperature and wet CO₂ density. For the conditions tested, the value of the coefficient is in the range of 0.015 to 0.056 cm/s. Greater temperature and smaller NaCl salinity increases the mass transfer coefficient. There is an interaction effect between temperature and wet CO₂ density, which increases or decreases the mass transfer coefficient depending on the value of each. CaCl₂ salinity does not have a statistically significant effect on the mass transfer coefficient. The transport calculations demonstrate that wellhead co-injection of CO₂ and brine is feasible, providing the same technical outcome at lower cost. For example, assuming a 2000 ft deep well and typical aquifer injection conditions, complete dissolution of the bulk COv phase can be achieved at 670 ft for bubbles of 0.16 cm initial radius. Using a horizontal pipe or mixing tank was also shown to be feasible. Gas entrainment was shown to provide a marked reduction in size of mixing apparatus required. / text

Carbon capture, utilization and storage (CCUS) aims to reduce CO₂ emissions by capturing CO₂ from sources and injecting it into geologic reservoirs for enhanced hydrocarbon recovery and storage. One concern is that unintentional CO₂ and reservoir gas release to the surface may occur through seepage pathways such as fractures and/or improperly plugged wells. We hypothesize that CO₂ and CH₄ migration into the vadose zone and subsequent O₂ dilution and Eh and pH changes could create an increased potential for metal mobilization, which could potentially contaminate ground and surface waters. This potential has not been addressed elsewhere. Goals of this study are to understand how the potential for metal mobilization through soil pore water may increase due to CO₂ and CH₄ and to assess potential impact to aquifers and/or the biosphere. The study was conducted at a CCUS site in Cranfield, MS, where localized seepage of CH₄ (45%) from depth reaches the surface and oxidizes to CO₂ (34%) in the vadose zone near a plugged well. Four sediment cores (4.5-9m long) were collected in a transect extending from a background site through the area of anomalously high soil gas CO₂ and CH₄ concentrations. Sediment samples were analyzed for Eh and pH using slurries (1:1 vol. with DI water) in the field and for occluded gas concentrations, metal (Ba, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) concentrations, moisture content, organic carbon content, and grain size in the laboratory. Data from the background reference area (no gas anomaly: occluded gas ~21% O₂, <1% CO₂, 0% CH₄) showed oxidized conditions (Eh from 464-508mV) and neutral pH (7.0-7.8) whereas samples collected near the gas anomaly (13-21% O₂, 0.1-5% CO₂, <0.1% CH₄) were more reducing (Eh 133-566mV) and more acidic (pH = 5.3-8.0). Significant correlations were found between Eh and O₂ (r = 0.95), pH and CO₂ (r = -0.88), and between these parameters and acid-leachable metals in samples from within the soil gas anomaly. Correlations quickly weaken away from the anomaly. Statistically, total metal concentrations, except for Ba, are similar in all cores. Acid-mobile metal concentrations, above 5m, increase toward the gas anomaly. The percent of water-mobile metals is very low (<2%) for all metals in all cores, indicating freely-mobile metals are not affected by elevated CO₂/CH₄. Conclusions are: 1) oxidation of CH₄ to CO₂ depletes O₂ causing reducing conditions; 2) high CO₂ and low O₂ affect Eh and pH of sediments which in turn alters mineralogy and bond strength between sediments and adsorbed ions; 3) intrusion of strongly acidic fluids (pH of acid used was 0.39) into these sediments could potentially remove weakly bonded metals or dissolve minerals. Implications from this study are that Eh needs to be considered along with pH when analyzing contamination potential, and that exposure of sediments to reducing, followed by acidic conditions, increases the potential for metal mobilization in the vadose zone. More research is needed to determine the concentration of gases (CO₂, CH₄ and O₂) that will create Eh and pH levels that could affect the mineralogy and sorption mechanism potentially leading to metal mobilization. Methods for assessing potential metal mobilization may be useful for site characterization and risk assessment. / text

The injection operator for a carbon dioxide sequestration project must control the reservoir and associated pore space within the project boundaries to allow for orderly development of the storage facility. A large number of interest owners within a project area is likely to make reaching unanimous agreement among all owners of pore space unlikely, and thus control of the reservoir difficult. In order to facilitate geologic sequestration of carbon dioxide on privately owned land in the United States, or on land for which the minerals or pore space are privately owned, a scheme for aggregating the ownership of pore space is needed. To allow geologic sequestration projects to move forward with less than unanimous consent of interest owners, states can employ various methods of aggregating pore space ownership. This paper examines oil and gas unitization statues and statutes creating groundwater districts to find legislative regimes useful for achieving pore space ownership aggregation. Among the approaches discussed, aggregation of pore space ownership through a unitization model is the most likely choice. Taking that one step further and setting up new unit operating agreements for enhanced oil recovery to serve as a repository for incremental geologic sequestration, and eventual full sequestration activities, provides a firm path toward reducing carbon dioxide emissions while respecting property rights. This paper also compares the few existing pore space aggregation statutes in the United States, which achieve aggregation of pore space ownership through either unitization or eminent domain. The state that appears to be the best equipped to deal with aggregation of pore space ownership is Wyoming. Wyoming has been a leader in developing legislation to deal with pore space ownership before other states. North Dakota and Utah are also very well situated to move forward with carbon sequestration activities. / text

No description available.

Greenhouse gases such as carbon dioxide (CO2) may be to blame for a gradual rise in the average global temperature. The state of Texas emits more CO2 than any other state in the U.S., and a large fraction of emissions are from point sources such as power plants. CO2 emissions can be offset by sequestration of produced CO2 in natural reservoirs such as coal seams, which may initially contain methane. Production of coalbed methane can be enhanced through CO2 injection, providing an opportunity to offset the rather high cost of sequestration. Texas has large coal resources. Although they have been studied there is not enough information available on these coals to reliably predict coalbed methane production and CO2 sequestration potential. The goal of the work was to determine if sequestration of CO2 in low rank coals is an economically feasible option for CO2 emissions reduction. Additionally, reasonable CO2 injection and methane production rates were to be estimated, and the importance of different reservoir parameters investigated. A data set was compiled for use in simulating the injection of CO2 for enhanced coalbed methane production from Texas coals. Simulation showed that Texas coals could potentially produce commercial volumes of methane if production is enhanced by CO2 injection. The efficiency of the CO2 in sweeping the methane from the reservoir is very high, resulting in high recovery factors and CO2 storage. The simulation work also showed that certain reservoir parameters, such as Langmuir volumes for CO2 and methane, coal seam permeability, and Langmuir pressure, need to be determined more accurately. An economic model of Texas coalbed methane operations was built. Production and injection activities were consistent with simulation results. The economic model showed that CO2 sequestration for enhanced coalbed methane recovery is not commercially feasible at this time because of the extremely high cost of separating, capturing, and compressing the CO2. However, should government mandated carbon sequestration credits or a CO2 emissions tax on the order of $10/ton become a reality, CO2 sequestration projects could become economic at gas prices of $4/Mscf.

No description available.

Life cycle analysis is carried out for 11 predicted configurations of pyrolysis biochar systems to determine greenhouse gas balance, using an original spreadsheet model. System parameters reflect deployment in Scotland, and results demonstrate that all major crop and forestry feedstocks offer greater GHG abatement than other bioenergy technologies, regardless of system configuration. Sensitivity analysis determines the relative importance of uncertain variables in the model and optimistic to pessimistic scenarios are used for system operation. Slow pyrolysis is compared to fast pyrolysis and biomass co-firing for GHG abatement and electricity production, using various scenarios for availability of indigenous Scottish feedstocks.