NO3 reduction for flue gas cleaning using wet-type plasma reactor
ABSTRACT Fundamental characteristics of the flue gas cleaning for NOx using the wet-type plasma reactor has been evaluated, with attention being laid on concentration of nitrate and ammonium ions in the liquid. The wet-type plasma reactor was a wire-cylinder, driven by square wave high voltage pulse. A thin liquid film was maintained on the inner wall of the reactor. In this reactor, discharge plasma oxidizes NO to NO2, and NO2 is dissolved into the liquid as HNO3. Continuous absorption induces saturation and acidification of the liquid, inhibiting the absorption of NOx. Effect of the NH3 addition for enhancement of NOx removal has been experimentally confirmed. The NH3 addition was effective for NO oxidation as well as NOx absorption into the liquid, resulting in the increasing of NO2- and NO3+ concentration in the liquid. With the presence of Fe ions in liquid exposed to the discharge plasma, reduction can be made from NO3- to NH4+ through the oxidation of Fe2+ to Fe3+. The reductive reaction enhances the absorption of NOx. These results suggest the possibility of the continuous operation of the wet-type plasma reactor for NOx removal without excess acidification of the absorbing water, nor feeding additives.
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ABSTRACT: In this paper, the authors report the results of laboratory experiments on NO<sub>x</sub> removal (DeNOx) using a nonthermal plasma process. Studies were conducted on a dry-type plasma reactor and several wet-type reactors to evaluate DeNOx efficiency. The reactor geometry was coaxial with an inner discharge electrode and an outer ground electrode wrapped on an insulating glass tube. Simulated flue gas was used in the experiment. The dry-type reactor performed better with the addition of ammonia and water vapor to the simulated gas. In the wet-type reactors, water and NaOH solution were used as absorbents and DeNOx performance was found to be the same in each case. Also, with water as the absorbent and with its pH value dropping below 3, the performance of the wet-type reactors remained constant. Studies on wet-type reactors, further, suggested that about half of NO removed by the plasma was dissociated into N<sub>2</sub> and O<sub>2</sub> and the rest was absorbed by water. The studies indicate that wet-type reactors performed better than the dry-type reactor in the removal of NO<sub>x</sub>IEEE Transactions on Industry Applications 12/1995; · 1.67 Impact Factor
Conference Proceeding: The influence of reaction conditions on SO2 oxidation in a discharge plasma reactor[show abstract] [hide abstract]
ABSTRACT: In this work, we report several approaches for the removal of SO <sub>2</sub> using nonthermal pulsed discharge plasma processing under absence of NH<sub>3</sub>. The gas-phase reaction was found to be less attractive due to its high energy cost. The increase in temperature decreased the SO<sub>2</sub> removal rate, resulting in high energy cost. In case of the wet type plasma reactor, the discharge plasma greatly enhances the liquid phase oxidation of SO<sub>3</sub><sup>2- </sup> to SO<sub>4</sub><sup>2-</sup>. The presence of TiO<sub>2</sub> catalyst increased the gas phase oxidation and the liquid phase oxidation as wellIndustry Applications Conference, 1999. Thirty-Fourth IAS Annual Meeting. Conference Record of the 1999 IEEE; 02/1999
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ABSTRACT: The objective of our research is to design a single-well injection-withdrawal test to evaluate residual phase trapping at potential CO2 geological storage sites. Given the significant depths targeted for CO2 storage and the resulting high costs associated with drilling to those depths, it is attractive to develop a single-well test that can provide data to assess reservoir properties and reduce uncertainties in the appraisal phase of site investigation. The main challenges in a single-well test design include (1) difficulty in quantifying the amount of CO2 that has dissolved into brine or migrated away from the borehole; (2) non-uniqueness and uncertainty in the estimate of the residual gas saturation (Sgr) due to correlations among various parameters; and (3) the potential biased Sgr estimate due to unaccounted heterogeneity of the geological medium. To address each of these challenges, we propose (1) to use a physical-based model to simulation test sequence and inverse modeling to analyze data information content and to quantify uncertainty; (2) to jointly use multiple data types generated from different kinds of tests to constrain the Sgr estimate; and (3) to reduce the sensitivity of the designed tests to geological heterogeneity by conducting the same test sequence in both a water-saturated system and a system with residual gas saturation. To perform the design calculation, we build a synthetic model and conduct a formal analysis for sensitivity and uncertain quantification. Both parametric uncertainty and geological uncertainty are considered in the analysis. Results show (1) uncertainty in the estimation of Sgr can be reduced by jointly using multiple data types and repeated tests; and (2) geological uncertainty is essential and needs to be accounted for in the estimation of Sgr and its uncertainty. The proposed methodology is applied to the design of a CO2 injection test at CO2CRC's Otway Project Site, Victoria, Australia.International Journal of Greenhouse Gas Control. 01/2010;