| 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. During this quarter in the Oxycoal Team continued to enhance the particle shadow velocimetry (PSV) technique by adding a robust image processing software module. Preliminary tests were carried out on the pilot-scale oxy-fuel combustor (OFC), and the images acquired during these tests were used to test the newly developed algorithms. The Team also continues to work on the flue gas recycle system for the OFC and integrating results from several tasks into the topical report for this task. The Gasification Team continued to analyze the CANMET gasifier data and continued development and implementation of a more advanced radiation property calculator, the full-spectrum k-Distribution method. Various filtering options were explored. Timing versus accuracy studies between reverse Monte adaptive-focus mesh was also implemented to further enhance scalability and speed. The experimental efforts included measurement of the steam gasification reactivity of Illinois #6 char at 10 and 15 atm, production of fully pyrolized Illinois #6 char at 12.5 atm to re-inject later in gasification experiments, and measurement of centerline gas temperature profiles in HPFFB reactor at 10, 12.5, and 15 atm. During this quarter, a new apparatus for performing gasifier spray evaluation was constructed, and high loadings of petroleum coke (petcoke)-water slurry (PCWS) were evaluated as well as some lower loadings of coal-water slurry (CWS). The CWS results follow agree with the literature, while the PCWS data shows more discrepancies, possibly because of the higher solids loading. The micro-hole atomizer design showed a marked improvement over previous designs. It offered stable and reliable performance during the experimental campaigns on the entrained-flow gasifier (EFG). The EFG temperature profiles during operation, the syngas composition, and the relative amounts of slag and/or char collected from the EFG post-run indicate the atomizer design is working well. In addition, the sampling probe for the EFG was successfully operated at a pressure of 200 psig and a high temperature of 2700°F at the middle of the reaction zone. The gasifier was run at traditionally defined stoichiometric ratios ranging from ~0.43 to ~0.65 with a Utah bituminous coal. The sampling procedure worked well, but samples were not taken long enough to clear the sample lines of nitrogen purge gas, so concentrations of syngas were very low. During this quarter, the CLC Team continued to develop an understanding the kinetics of both oxidation and decomposition of CuO/Cu2O. The work attempts to explain the reason for an uncommon characteristic occurring during the oxidation of Cu2O to CuO, where the reaction rate slows with increasing temperature at higher temperatures. Others have suggested this to be a factor of an increased equilibrium partial pressure of oxygen (corresponding to a decreased driving force). While accounting for the partial pressure driving force decrease, it became apparent that the oxidation of Cu2O operates in two temperature regimes with two different activation energies suggesting that the driving force is not the only factor in the decreased rate of oxidation. In addition, constants in the general rate expression have been determined and are reported here. In addition, progress on the high-performance simulations continued: we continued to refine the breakage/coalescence kernels for particle interactions in multi-fluid simulations. We also started to explore some theoretical aspects of the Direct Quadrature Method of Moments (DQMOM) related to its formulation in terms of a more general technique that allows us to use a more flexible method for quadrature approximations. We have prioritized the Eulerian-Eulerian approach over the Discrete Element Method (DEM) because of the reduced computational cost of the Eulerian-Eulerian approach. Finally, the investigators continued to work on publications for peer reviewed journals and contributions to the CLC topical report. The UCTT Team performed a preliminary study of the effect of volumetric confinement on porosity evolution during pyrolysis in bituminous coal. A small aluminum vessel was used to prevent swelling of a 2 cm coal core during pyrolysis. A control experiment was also performed with a core that had full freedom to swell during pyrolysis. Results from these experiments were compared to previous experiments. A series of experiments operating at different heating rates, final temperatures, pressures and coal types were performed. In addition, we have continued to improve our HPC based simulation tools for underground thermal treatment of coal by coupling our operator splitting algorithm with the variability of coal properties based on depth and temperature into our Star-CCM+ simulation. The UCTT Team also completed the CH4 and CO2 isotherms on the raw coals and found that Skyline coal has the lowest adsorptive capacity. The adsorptive capacity of the Carlinville (Illinois) is similar to the Skyline coal. The Powder River Basin coal showed the highest adsorptive capacity. The results of the high-pressure isotherms on the raw coals are in agreement with the low-pressure isotherms taken with the BET surface area analyzer. They also performed preliminary simulations showing the injection of CO2 into a partially pyrolized coal seam using GEM (with isotherms for Skyline coal pyrolyzed at 325°C). The simulation results showed that for the modeled domain size and a CO2 injection rate of 6000m3/day, breakthrough occurs within hours. The simulation also showed that over the course of a year that 7.28 x107 gmole CO2 (8.72E7 SCF) could be sequestered by adsorption. Task 9 efforts focused primarily on optimizing LES simulations of the BSF to minimize computing time. The investigators considered initial gas concentration, the solution interval for the radiation model, the order of the explicit solver, the coal feed rate, coal particle size, inlet flow temperature and wall temperature. |
