Papers by Keyword: NO

Abstract: Many studies have indicated that carbon can be reduced to nitric oxide. This paper reports an experimental study of NO reduction by mixed materials of biochar or active carbon with cement raw meal. The proportion of mixed materials was 95 wt.% cement raw meal and 5 wt.% biochar or active carbon. A mixture loading amount and gas flow rate study quantifying the effect of carbon amount and gas residence on the reduction of nitric oxide was carried out. The experiment was performed in a fixed bed reactor at the temperature of 800°C, with O₂ concentration of 1%. The inlet NO concentration was 1000 ppm. The characterization of structure and properties of biochar and active carbon was conducted by SEM-EDS, BET. The results show that different carbon materials have different NO reduction effect. The NO conversion rate increases with the increase of the amount of mixture loading. This method of removing NO is practically feasible.

Abstract: Effects of NO and forming gas annealing treatment on the interface quality and reliability of 4H-SiC MOS were systematically studied by low temperature conductance measurements in combination with time-zero dielectric breakdown and time-dependent dielectric breakdown methods. The interface trap density (D_it) showed no obvious reduction after forming gas annealing, and the values of D_it decreased significantly after combined NO and forming gas annealing treatment. The F-N barrier height, electric field to breakdown (E_bd) and charge to breakdown (Q_bd) of the MOS structure increased from 2.42 eV, 10 MV/cm, 1mC/cm² to 2.62 eV, 10.7 MV/cm, 78mC/cm² after forming gas annealing. The values of F-N barrier height, E_bd and Q_bd for MOS capacitors with combined NO and forming gas annealing treatment are 2.69 eV, 10.2 MV/cm, and 24mC/cm². These results suggest that forming gas annealing is more effective in reliability improvement. While when considering the interface trap density, it seems that combined NO and forming gas annealing treatment is a better choice.

Abstract: We study the impact of different nitric oxide (NO) post oxidation annealing (POA) procedures on the on resistance R_on of n-channel MOSFETs and on the threshold voltage shift ∆V_th following positive bias temperature stress (PBTS). All samples were annealed in an NO containing atmosphere at various temperatures and times. A positive stress voltage of 30 V was chosen which corresponds to an electric field of about 4.3 MV/cm. The NO POA causes a decrease in overall ∆V_th for longer NO POA times and higher NO POA temperatures. As opposed to the change in ∆V_th, the device R_on increases with NO POA temperature and time.

Abstract: Lateral MOSFET devices with a thin surface counter-doped layer using Sb and As with and without NO passivation have been fabricated and characterized. The results demonstrate that Sb and As counter-dope the interface without significant trap passivation while in combination with NO there is a superposition of both trap passivation and counter-doping related performance enhancement. In addition, by varying the counter doping level, a universal mobility characteristics of NO passivated devices has been identified.

Abstract: In order to generate powerful radicals as oxidizing species for the complete oxidation of NO, homogeneous activation of peroxymonosulfate (Oxone: PMS) by the Mn₃O₄/GO catalysts was explored. The catalytic oxidation of NO from waste gas was investigated using advanced oxidation process based on sulfate radicals that produced. The manganese oxide immobilized on graphene oxide (GO) can activate PMS for the oxidation of NO in water. We not only took advantage of the high oxidation–reduction potential of produced sulfite radicals but also an opportunity to oxidize NO on less complex compounds with low dosages. The Mn₃O₄/GO catalysis system was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that Mn₃O₄ was well-distributed on GO. The Mn₃O₄/GO catalyst system exhibited high efficiency for NO oxidation when the Mn₃O₄/GO catalyst has an optimum Mn₃O₄ loading. In addition, the best catalytic oxidation can be achieved within 30 min with pH 4 and 6 mM PMS at 25 °C. Therefore, the results indicate promising potential for a system utilizing Mn₃O₄/PMS to oxidize NO for offgas treatment.

Abstract: There are variety of active substances in Fenton system, such as H₂O₂, HO₂^-, O₂^-·, ·OH and HO₂·. In this paper, the oxidation of H₂O₂, HO₂^-, O₂^-·, ·OH and HO₂· on NO gas was determined respectively with experimental methods. The results showed that direct oxidation of gaseous NO by H₂O₂, HO₂^- and O₂^-·was weak. ·OH and HO₂· had strong oxidizing capacity on gaseous NO, especially ·OH. With the acceleration of ·OH and HO₂· generation rate, the oxidizability of Fenton system on NO gas was stronger, but O₂ generation rate also accelerated. Rapid decomposition of H₂O₂ is the premise to realize high NO oxidation efficiency using H₂O₂, but how to avoid the invalid decomposition of H₂O₂ is the key to increase use ratio of H₂O₂.

Abstract: In this paper, a tube electric furnace is used to process the co-combustion of biomass and crude oil in air atmosphere, the influence of the biomass mass fraction and the temperature on NO and SO₂ emissions are analysed. Research shows that with the increasing addition ratio of biomass to crude oil, the amount of NO in per unit heat reduces. This tendency is more apparent at high temperatures. Compared with crude oil, the NO emission of 20% biomass mass fraction at 1100°C is reduced by 25.8% while 19.02% at 700°C. SO₂ emission in per unit heat decreases with the increasing biomass mass fraction. This tendency is more apparent at low temperatures. Compared with crude oil The generation of SO₂ of 20% biomass mass fraction can reduce 91.5% at 700°C while 36.7% at 1100°C.

Abstract: Different Cu-loading pillared clays catalysts were studied in selective catalytic reduction of NO by propylene. The catalyst prepared by incipient wetness impregnation (Cu/Ti-PILCs) had better catalytic activity and stability than that prepared by ion-exchanged method (Cu-Ti-PILCs). Cu/Ti-PILCs has higher BET surface area than Cu-Ti-PILCs. Pore size distribution analysis and XRD showed that Cu species dispersed well in Cu/Ti-PILCs but formed conglomeration in Cu-Ti-PILCs. TPR showed that Cu²⁺ species were the main active species on the Cu/Ti-PILCs, which was responsible for the high catalytic activity of catalyst.

Abstract: The effect of MgO addition on SO₂ tolerance of MnO_x for the NO catalytic oxidation was investigated in this work. MgO addition significantly promotes the SO₂ resistance of MnO_x at low temperature range of 50–250°C. The slight decrease in catalytic activity over Mn-Mg-O_x exposure to SO₂ is attributed to the partially deactivation of the catalytic active site poisoned by SO₂. Through XRD and FT-IR characterization, MgO may effectively inhibit the competitive adsorption between NO_x and SO₂ in manganese site, and enhance SO₂ adsorption on the magnesia surface.

Abstract: For study on SO2 and NO emission characteristics of circulating fluidized bed boiler experiments were carried out in a 300MW circulating fluidized bed boiler. In these experiments, the variables were the amount of limestone and bed temperature. While conducting the test, the reasons for the changes in emission were analyzed, and some advices about combustion adjustment were proposed.