| Description |
The University of Utah is pursuing research to utilize the vast energy stored in our domestic coal resources and to do so in a manner that will capture CO2 from combustion from stationary power generation. The research is organized around the theme of validation and uncertainty quantification through tightly coupled simulation and experimental designs and through the integration of legal, environment, economics and policy issues. The results of the research will be embodied in the computer simulation tools which predict performance with quantified uncertainty; thus transferring the results of the research to practitioners to predict the effect of energy alternatives using these technologies for their specific future application. A summary of highlights from the last quarter follows. The Oxycoal simulation team completed a validation study of particle behavior in non-reacting coaxial particle-laden jets and a preliminary study of the oxy-fuel combustor (OFC). For non-reacting cases, large eddy simulations (LES) proved capable of modeling particle velocities and particle dispersion in coaxial jet with a good agreement with experimental data. Simulations of the OFC focused on the effect of partial pressure of oxygen in the primary stream, which is the first parameter chosen for the validation/UQ study, on the flame stand-off distance. The oxy-coal single particle circulating fluidized bed (CFB) focused on further development of multi-grain single coal particle combustion model and predictions of O2 diffusion limited layer in large coal particle combustion. The Oxycoal experimental team began experiments using a burner equipped with a pure oxygen stream and measured stand-off distance and NOx and SOx emissions in the OFC. They also analyzed the PIV results from the OFC to highlight the differences in the velocity fields of coal particles in oxy-coal flames at different concentrations of the oxidizer and at various locations in the reaction zone. An experimental database of PIV results obtained is now available for validation/uncertainty quantification demonstration. The investigators also began fabrication of a new drop tube for ash partitioning studies and performed elemental analysis of drop-tube samples of Illinois #6 coal under O2/N2 and O2/CO2 combustion by scanning electron microscopy (SEM) and energy dispersive X-ray detector (EDS). Finally, the recently modified oxy-fired pilot-scale circulating fluidized bed (CFB) was used to study operational impacts of variations in oxygen concentration and limestone injection. This quarter, the several of the gasification subtasks (4.2, 4.4, 4.5, and 4.6) focused on the completion of their contributions to the gasification topical report. Gasification simulation work focused on repairing bugs in the chemical reaction and mixing table interface, which were causing unreasonable results. In addition, they performed verification testing of the Reverse Monte Carlo (RMCRT) algorithm. Additional physics were added to the RMCRT algorithm, allowing the algorithm to more closely match the conditions of combustion. During this quarter, the CLC simulation team completed a comparison of carbon consumption profiles from experimental data on CLOU combustion of Mexican Petroleum Coke and German Lignite with an in-house mathematical model. An order of magnitude calculation on particle heat up times was also performed, which incorporates fluidized-bed heat transfer coefficients calculated from correlations on a single particle and fluidized bed. They also developed a DEM geometry technique that helps create a cylindrically shaped moving-bed reactor representation in Star-CCM+. Thus far, they have considered two different particle designs: spheres and cylindrical elements. In addition, they completed preliminary fluid-only simulation around the particles to understand the characteristics of the fluid flow inside the moving bed reactor. The CLC experimental team completed lab-scale testing on a copper carrier obtained from Sigma Aldrich and continued testing with copper-based material obtained from the Institute for Chemical Processing of Coal in Poland. The material from Sigma Aldrich (SA) was 13 wt.% CuO on Al2O3. The Polish material (Pol) was received as 50 wt.% CuO on TiO2. Testing for this quarter focused primarily on the spontaneous release of oxygen from the carrier for CLOU. They also completed TGA studies of the oxidation of copper metal powder to cupric oxide under elevated pressures using air as the oxidant. Preliminary experiments confirmed the results reported in the literature. The TGA experimental procedures were revised, and the results indicate the absence of the pressure dependence, both predicted, and published previously. This finding is an important piece of new information for the design of an operating system, using the CLC/CLOU concept. The UCTT team tested a small fixed-bed reactor to study coal pyrolysis under in-situ thermal treatment conditions. A few improvements are necessary to continue collecting data. Design of a high-pressure bench-scale reactor for simulating coal bed pyrolysis is complete, and the reactor is being readied for fabrication at a manufacturer. They also finalized the DEM geometry technique that helps create smooth particle edges for a proper computational mesh in Star-CCM+. In addition, they increased the size of the computational domain to more closely resemble our validation geometry. Lastly, they evaluated the effect of boundary conditions on both the simulation settings and the concurrent design of experimental apparatus, using a simplified geometry. The sequestration team focused on comparing the experimental data for the CO2 and CO2+SO2 cases with geochemical modeling using Geochemists Workbench. The modeling results were able to capture the trends in the experimental data by adjusting the model parameters, such as active surface area. |
