Self-Assembly and the Properties of Micro-Mesoporous Carbon.

This study introduces a new approach for constructing atomistic models of nanoporous carbon by randomly distributing carbon atoms and pore volumes in a periodic box and then using empirical and ab initio molecular simulation tools to find the suitable energy-minimum structures. The models, consisting of 5000, 8000, 12000, and 64000 atoms, each at mass densities of 0.5, 0.75, and 1 g/cm3, were analyzed to determine their structural characteristics and relaxed pore size distribution. Surface analysis of the pore region revealed that sp atoms exist predominantly on surfaces and act as active sites for oxygen adsorption. We also investigated the electronic and vibrational properties of the models, and localized states near the Fermi level were found to be primarily situated at sp carbon atoms through which electrical conduction may occur. Additionally, the thermal conductivity was calculated using heat flux correlations and the Green-Kubo formula, and its dependence on pore geometry and connectivity was analyzed. The behavior of the mechanical elasticity moduli (Shear, Bulk, and Young's moduli) of nanoporous carbons at the densities of interest was discussed.

Computer simulation of carbonization and graphitization of coal.

This study describes computer simulations of carbonization and graphite formation, including the effects of hydrogen, nitrogen, oxygen, and sulfur. We introduce a novel technique to simulate carbonization, 'Simulation of Thermal Emission of Atoms and Molecules (STEAM)', designed to elucidate volatile outgassing and density variations in the intermediate material during carbonization. The investigation analyzes the functional groups that endure through high-temperature carbonization and examines the graphitization processes in carbon-rich materials containing non-carbon impurity elements. The physical, vibrational, and electronic attributes of impure amorphous graphite are analyzed, and the impact of nitrogen on electronic conduction is investigated.

Integration of novel hybrid composite discharge electrode with semi-pilot novel cross-flow electrostatic precipitator.

Wet electrostatic precipitators (WESPs) are modern-era pollution control systems specifically designed to capture ultrafine particles as well as acid mist, highly resistive and sticky particles; however, this requires the use of expensive corrosion-resistant metal alloys. The work presented here is part of a continuing study at Ohio University aimed at reducing the cost of WESPs by using a novel combination of a polymer collector surfaces with a hybrid composite discharge electrode. In this study, a hybrid composite discharge electrode was tested, for the first time, inside a semi-pilot-scale experimental setup, with collection surfaces consists of a vertical array of strands. Particle laden gases were passed through this array of polymer ropes, which were kept wet by a small flow of water. The discharge electrodes were composite laminates of carbon fibers in a polymer matrix enclosing a metal mesh. The preliminary results showed that this new integrated system of composite discharge electrode and polymer collector surfaces can match or exceed the performance of a conventional metal alloy electrostatic precipitator (ESP) with metal discharge electrodes. There are additional advantages due to the system being compact, lightweight, and highly corrosion resistant. Implications: This study focused on integrating and assessing performance of a novel hybrid composite electrode (HCE) inside semi-pilot novel cross-flow electrostatic precipitator at conditions typically observed in coal-fired power plant exhausts. The results were collected for particulate collection efficiencies and were compared with a rigid metal electrode. The HCE outperformed metal electrode by showing higher particulate collection efficiency. This result showcases substantial potential for these two new technologies (HCE and cross-flow system) as a substitute for conventional metal based wet ESPs.

Novel hybrid composite discharge electrode for electrostatic precipitator.

Over the last few decades, electrostatic precipitators (ESPs) have emerged as effective air pollution control devices for treating coal-fired power plant exhausts. Among the components of the ESP, the discharge electrodes are extremely important in determining the collection efficiency of the ESP. Typically, in wet ESPs, the discharge electrodes used must be made of corrosion-resistant alloys, which makes them extremely expensive and heavy. Hybrid composite discharge electrodes have the potential to be lightweight and corrosion-resistant substitute for traditional metal alloy electrodes used in wet ESPs. In this experimental study, a novel hybrid composite electrode (recently patented at Ohio University) is presented as a substitute for traditional metal electrodes in wet ESPs. The samples of hybrid electrodes were fabricated by using carbon fiber composites, combined with metal mesh, in the shape of a long and thin tape. The electrode's electrical response was evaluated in open atmospheric conditions, while connected to a transformer-rectifier unit to generate a corona current at voltages exceeding 50 kV. Results of these hybrid electrodes were compared with traditional metal electrodes. The hybrid composite discharge electrode produced a uniform corona at comparable power levels to that of metal electrodes, with additional advantages of being compact, lightweight, and highly corrosion resistant. In addition, hybrid composite electrodes exhibited lower corona onset voltage as compared with metal electrodes. The preliminary experimental data are encouraging and show significant potential for this new inexpensive hybrid electrode to replace metal electrodes in wet ESPs, providing comparable (and in some cases exceeding) collection efficiencies with lower ozone generation. IMPLICATIONS: The newly invented hybrid composite electrode (HCE) performance was evaluated through experimentation with conventional metal electrodes. The HCE performance was comparable to the metal electrodes. The HCE also exhibited uniform corona fields and steady power while maintaining similar and in some cases superior electrical performance as compared with metal electrodes and thus shows a significant potential to substitute metal electrodes in wet ESP systems.