Abstract:The high cost of a currently available selective catalytic reduction (SCR) process is driving R&D
efforts toward finding alternative technologies to remediate NO emissions from utility boilers.
A hybrid plasma−catalyst (P−C) system is investigated for NO
x
removal. The plasma (dielectric
barrier discharge) and SCR techniques are each studied for the reduction of NO
x
for comparative
purposes. γ-Al2O3 is used as a catalyst in the hybrid P−C system. The hybrid P−C experiments
show effective NO
x
removal compa… Show more
“…A brief description of the main equipment and the procedures used to obtain experimental results are presented below. Details are available elsewhere. ,, 1 Schematic diagram of benchtop system.…”
Section: Experimental Apparatus and Proceduresmentioning
confidence: 99%
“…There are excellent publications on the mechanistic understanding of electrical discharge, electron distribution, and other properties of plasma. − In our approach, a dielectric is placed between two electrodes, allowing a barrier discharge to occur through which the gases are made to flow. We have successfully applied this DBD technique in our laboratory for the oxidation of NO x and SO 2 and the decomposition of freons. − The key steps involve electroimpact dissociation of O 2 forming metastable oxygen atoms which react with most NO, forming NO 2 . NO 2 then interacts with OH resulting from electroimpact dissociation of H 2 O, producing byproduct nitric acid (HNO 3 ).…”
The pronounced volatility of elemental mercury (Hg0) and some of its compounds, coupled with their extreme
toxicity, makes these substances extremely hazardous. Conversion of Hg0 to HgO would significantly enhance
mercury removal from flue gases. This investigation is focused on studying the effect of some of the constituents
such as O2, H2O, CO2, and NO
x
present in flue gases on elemental mercury oxidation in a dielectric barrier
discharge (DBD) reactor. The results show that Hg vapors (6 ppbv) in a stream of 0.1% O2 and N2 are
effectively oxidized at the energy density of up to 114 J/L. Hg conversion of over 80% is achieved when
present in a gas mixture of 8% O2, 2% H2O, and 10% CO2 in N2 balance. The presence of NO
x
enhanced
mercury oxidation in the DBD reactor. The oxidation chemistry is discussed. Studies show that Hg can be
simultaneously removed along with the other two major pollutants, NO
x
and SO2, in one DBD reactor followed
by a wet scrubber system. This avoids the need of three techniques for the removal of major gaseous pollutants
from coal-fired power plants.
“…A brief description of the main equipment and the procedures used to obtain experimental results are presented below. Details are available elsewhere. ,, 1 Schematic diagram of benchtop system.…”
Section: Experimental Apparatus and Proceduresmentioning
confidence: 99%
“…There are excellent publications on the mechanistic understanding of electrical discharge, electron distribution, and other properties of plasma. − In our approach, a dielectric is placed between two electrodes, allowing a barrier discharge to occur through which the gases are made to flow. We have successfully applied this DBD technique in our laboratory for the oxidation of NO x and SO 2 and the decomposition of freons. − The key steps involve electroimpact dissociation of O 2 forming metastable oxygen atoms which react with most NO, forming NO 2 . NO 2 then interacts with OH resulting from electroimpact dissociation of H 2 O, producing byproduct nitric acid (HNO 3 ).…”
The pronounced volatility of elemental mercury (Hg0) and some of its compounds, coupled with their extreme
toxicity, makes these substances extremely hazardous. Conversion of Hg0 to HgO would significantly enhance
mercury removal from flue gases. This investigation is focused on studying the effect of some of the constituents
such as O2, H2O, CO2, and NO
x
present in flue gases on elemental mercury oxidation in a dielectric barrier
discharge (DBD) reactor. The results show that Hg vapors (6 ppbv) in a stream of 0.1% O2 and N2 are
effectively oxidized at the energy density of up to 114 J/L. Hg conversion of over 80% is achieved when
present in a gas mixture of 8% O2, 2% H2O, and 10% CO2 in N2 balance. The presence of NO
x
enhanced
mercury oxidation in the DBD reactor. The oxidation chemistry is discussed. Studies show that Hg can be
simultaneously removed along with the other two major pollutants, NO
x
and SO2, in one DBD reactor followed
by a wet scrubber system. This avoids the need of three techniques for the removal of major gaseous pollutants
from coal-fired power plants.
“…Recently, nonthermal plasma decomposition seems to be an appropriate and promising technique for reducing the emission of various gaseous pollutants, including fluorinated compounds (Mok et al 2008;Zhu et al 2008), chlorofluorocarbons (Kang 2002), volatile organic compounds (Holzer et al 2002), nitric oxide (Chen and Mathur 2003) sulfur dioxide (Ma et al 2002), hydrogen sulfide (Yavorsky and Znak 2009), etc. Several researchers have proposed a variety of plasma discharge techniques such as pulsed corona discharge, microwave plasma discharge and dielectric barrier discharges (DBD), so far.…”
The performance of 1,1,1,2-tetrafluoroethane or HFC-134a decomposition and the formation of byproducts in a dielectric barrier discharge plasma reactor were studied with different packing systems such as a-Al 2 O 3 (porous and nonporous), c-Al 2 O 3 (porous) and ZrO 2 (nonporous). Experimental variables such as reactor temperature, initial HFC-134a concentration and oxygen levels were chosen for the performance analysis. Among the packing systems, the porous c-Al 2 O 3 and a-Al 2 O 3 decomposed HFC-134a much more effectively than the nonporous a-Al 2 O 3 and ZrO 2 . The combination of the plasma with the porous cAl 2 O 3 was found to cover a wide range of initial concentration. The decomposition efficiency tended to increase with the addition of oxygen up to 2 %, but further increase in the oxygen led to a decrease. As well as carbon oxides (CO 2 and CO), significant amounts of unwanted byproducts such as COF 2 and CF 4 were also identified in the effluent gas with the nonporous a-Al 2 O 3 and ZrO 2 . On the contrary, with the porous c-Al 2 O 3 and a-Al 2 O 3 , such unwanted byproducts were considerably suppressed, enhancing the formation of CO 2 and CO.
“…Applied practically in the daily life, it has been successfully used to commercialize the production of ozone [29] for air cleaning and sterilization during the past century. Recently, with the renewed interests in applications of atmospheric non-equilibrium plasmas, a great deal of efforts has been attempted to use the DBD in other applications such as flue gas decomposition [30,31], surface treatment [32], plasma coating [33], thin-film deposition [34], cleaning and activation of substrates [35] and plasma display panel [36]. However, little work has been carried out on the application of DBD to the analytical purpose.…”
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