Papers by Keyword: Non-Thermal Plasma

Abstract: This paper delves into the understanding of how dielectric barrier discharge (DBD) non-thermal plasma (NTP) system affects the flue gas compositions and the synergistic effects of DBD-NTP and SCR systems using NTP-downstream-SCR configuration on nitric oxide reduction through the experimental investigation. Simple gas feeds were used to observe the interaction between gases when high voltage discharge was applied. Overall, DBD-NTP was effective in oxidising NO and NH₃ into NO₂ while also reducing NO in the presence of NH₃. When DBD-NTP was installed downstream the SCR catalyst, it demonstrated substantial additional deNOx and reduction of NH₃ slippage. This proposed SCR+DBD-NTP configuration showed a potential to help mitigate low deNOx performance at low temperatures.

Abstract: The plasma degradation process of Eosin yellow aqueous solution utilizing AC corona discharge generated above liquid with a type of pin to plate by utilizing multiple needles electrodesis investigated the influence of electrodes material and effect of ferrous sulfate on decoloration and the kinetics of process are discussed. The AC corona discharge plasma was generated in the air gap between tip of needles and the water surface. The experimental results indicate that the decoloration rate increases with using stainless steel electrodes and with increasing the concentration of FeSO₄. When dye concentration is 10 mg/L with pH of 3, the air gaps were 0.85 cm and the number of pins were 30, the decoloration rate went up to 97% in 60 min.

Abstract: The technology for mercury removal in coal-fired power plant is still under development. In the flue gas, elemental mercury is the main component of mercury, and is hard to be removed due to its high volatility and low solubility. So converting Hg⁰ to Hg²⁺ in or ahead of the FGD is significant to enhance mercury removal. In this work, plasma treatment method was used to prepare V₂O₅/TiO₂ catalysts for effectively oxidation of Hg⁰. Plasma treatment of V₂O₅/TiO₂ resulted in the improvement of mercury oxidation activity. The Hg⁰ oxidation efficiency of the catalysts treated by plasma is over 82% at 300 °C, which is about 30% higher than that of the untreated catalyst. The catalysts were characterized using SEM, BET and EPR. SEM results indicated that plasma treatment can create cracks and small particles on simple surface, however, calcinations cause sintering and agglomeration. The superior catalytic performance is mainly attributed to the formation of particles attached to the catalyst surface, the higher amount of V⁴⁺ ions and vacancies on the catalyst surface.

Abstract: Numerical calculations with time dependant one-dimensional fluid model are performed at various conditions in argon atmospheric pressure to calculate electrical characteristics and plasma parameters including charged and metastable molecules densities. The simulation results show after steady discharge are formed, the voltage of discharge gap nearly remain constant and the phase is 0.36π advance of the applied voltage; The current density are in the same period as the applied voltage, the phase is 0.58π ahead of the applied voltage; The steady state Ar are in high number density in the whole discharge gap; The Ar* number density appear peak at the middle of the discharge gap; The Ar⁺ number density appear peak in the negative bright area.

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: The toluene being abatement by non-thermal plasma combined with photocatalyst was studied in the paper. As one of main factors, the influence on toluene abatement efficiency of gas flow rate, initial concentration and electric field intensity was analyzed in the study. Furthermore, the energy efficiency was another important index which had been compared among the different padding including of no padding, γ-Al₂O₃ padding and TiO₂/γ-Al₂O₃ padding. The result of study showed that the technology of non-thermal plasma combined with photocatalyst had better buffer action against increasing of gas flow rate and initial concentration. When the abatement efficiency was more than 52%, the energy efficiency values had the tendency as TiO₂/γ-Al₂O₃ >γ-Al₂O₃ padding > no padding.

Abstract: Non-thermal plasma technique can be used to degrade radioactive liquid waste involving Tributylphosphate (TBP) producing in nuclear fuel reprocessing. The dissociation reaction caused by the collision of electrons with neutral molecules can generate active radicals which play a central role in removing TBP. And the electron reacting with vapor to generate OH radicals is the key reaction in removing TBP. A model is derived from the Boltzmann equation and molecule collision theory to predicate the dissociation reaction rate coefficients. Upon comparing with available literature, the model is confirmed to be acceptably accurate in general. Reaction rate coefficients of vapor dissociation in non-thermal plasma are derived according to the Arrhenius formula.

Abstract: The study makes SO₂ as the control object, using strong ionized plasma discharge method for experimental research on several influence factors. These influence factors include input voltage (V), SO₂ primary concentration (C_SO2), residence time (t), and frequency (f). The influence of these factors on desulfurization rate was analyzed by single variable experiment. The relation curve of single variable influence on desulfurization rate is concluded. We have designed an orthogonal experiment to analysis the significance level of these influence variables and the optimization of these variables was made after the rule of single variable experiment. The experimental results showed that: When SO₂ primary concentration(C_SO2),oxygen content(φO₂), H₂O content(φH₂O), the residence time of gas streams flowing the reactor(t), gas flux(Q), input voltage(V) and frequency(f) are respectively 140×10^-6(V/V)~160×10^-6(V/V), 21%(V/V), 2.1%(V/V), 0.85s, 0.16m³/h, 3.0kV and 5.4kHz, the tiptop desulfurization rate was over 80%.

Abstract: Applications of non-thermal plasma in methane catalysis combustion have attracted a lot of attentions in recent years due to its outstanding and unique properties. We summarized two kinds of hybrid systems of plasma and catalysts for methane combustion reaction and compared these two figurations. Results prove that combining non-thermal plasma and catalysts has an excellent performance for methane total oxidation compared with single ones.

Abstract: Non-thermal plasma (NTP) technology has a good application prospect in diesel after-treatment field, but few studies on the effects of NTP on PAHs emissions had been carried out. In this paper, the concentrations of PAHs at different loads before and after the treatment of DNTP were studied, combined the GC/MS analysis with external standard method. The results indicate that total concentrations of PAHs were 149.46, 102.44, 107.34 and139.69μg/m^-3 at 25% , 50%, 75%, 100% load, 2000r/min respectively before the treatment of DNTP and reduced to 88.96, 77.31, 88.51 and 138.22μg/m^-3 after the treatment of DNTP, with the largest decline up to 40.48%. The main components of PAHs were naphthalene, anthracene, phenanthrene, fluoranthene, and pyrene, etc. Before the treatment of DNTP, the concentrations of PAHs decreased firstly and then increased with the increase of load. The average concentrations of PAHs with different rings after the treatment of DNTP were decreased by 21.2%, 22.4%, 20.5% and 6.9%.