Potential Application of Pin-to-Liquid Dielectric Barrier Discharge Structure in Decomposing Aqueous Phosphorus Compounds for Monitoring Water Quality

Here, we proposed a pin-to-liquid dielectric barrier discharge (DBD) structure that used a water-containing vessel body as a dielectric barrier for the stable and effective treatment of aqueous solutions in an open atmosphere. To obtain an intense pin-to-liquid alternating current discharge using a dielectric barrier, discharge characteristics, including the area and shape of a ground-plate-type electrode, were investigated after filling the vessel with equivalent amounts of water. Consequently, as the area of the ground electrode increased, the discharge current became stronger, and its timing became faster. Moreover, we proposed that the pin-to-liquid DBD reactor could be used to decompose phosphorus compounds in water in the form of phosphate as a promising pretreatment method for monitoring total phosphorus in water. The decomposition of phosphorus compounds using the pin-to-liquid DBD reactor demonstrated excellent performance—comparable to the thermochemical pretreatment method—which could be a standard pretreatment method for decomposing phosphorus compounds in water.

Plasma generation using dielectric barrier discharge reactor for phenol degradation in batik wastewater

Batik wastewater contains phenolic compounds. Phenolic compounds are hematotoxic, hepatotoxic, and capable of causing mutagenesis and carcinogenesis in humans and other living organisms. Therefore, phenol compounds need to be degraded. This study uses plasma electrolysis method with Dielectric Barrier Discharge (DBD) reactor to degrade phenolic compounds in Batik wastewater. The purpose of this study was to characterize the Dielectric Barrier Discharge (DBD) reactor, to determine the effect of voltage and type of catalyst on phenol concentration, and to determine the interaction between voltage and catalyst type on the response of phenol concentration through analysis of variance (ANOVA). The result obtained from the characterization of the reactor is ignition voltage at 1400 Volt. The best degradation results of phenolic compounds were obtained in the treatment of Batik wastewater with FeSO4 catalyst at 2600 Volt. The phenol reduction in the best conditions reached 88.73%. Based on analysis of variance (ANOVA), voltage and quadratic catalyst variables affect the response of phenol concentrations in batik waste.

A Novel Dielectric Barrier Discharge (DBD) Reactor with Streamer and Glow Corona Discharge for Improved Ozone Generation at Atmospheric Pressure

Discharge mode is an important parameter for ozone synthesis by dielectric barrier discharge (DBD). Currently, it is still challenging to stably generate glow discharge with oxygen at atmospheric pressure. In this paper, a DBD reactor with a layer of silver placed between the electrode and the dielectric layer (SL-DBD) was developed. Experimental results show that both streamer and glow corona discharge were stably generated under sinusoidal excitation with a 0.5 mm discharge gap in a parallel-plate DBD, due to the increased electric field strength in the discharge gap by the silver layer. It was also found that, in the SL-DBD reactor, glow corona discharge enhances the discharge strength by 50 times. The spectral peak of O at 777 nm in SL-DBD is increased to 28,800, compared with 18,389 in a reactor with a streamer only. The SL-DBD reactor produces ozone with a concentration of as high as 150 g/m3 and shows good stability in an 8 h durability test.

Reduction of tar from biomass gasification using a dielectric barrier discharge reactor

A non-thermal plasma reactor was used to investigate its effectiveness in reducing the by-products from biomass gasification. Biomass is used for generating heat and power through gasification, which is a process of converting solid fuel to gaseous fuel at temperatures of 700 to 900 °C by operating a reactor in sub-stoichiometric conditions. This gas mixture can be utilized for liquid fuel synthesis or for fuel cells. However, the by-product of gasification consists of tar, which consists of oxygenates, ringed-aromatics, phenolic compounds, and polyaromatic hydrocarbons (PAH). Depending on the composition, the condensation temperature can be as high as 450 °C, fouling downstream equipment. In this study, a dielectric barrier discharge (DBD) reactor with a coil as the inner electrode was used to reduce toluene, a model tar compound. Toluene was injected into a mixing chamber that was heated to 900 °C, evaporating the toluene, and is entrained by nitrogen into the DBD reactor. High voltage is injected into the DBD reactor to initiate ionization, decomposing the toluene into lighter hydrocarbons. A sampling bottle submerged in an ice bath collects the residual toluene, and the resulting decomposition rate is as high as 70%.

Experimental Study on Simultaneous Desulfurization and Denitrification by DBD Combined with Wet Scrubbing

A dielectric barrier discharge (DBD) reactor combined with a wet scrubbing tower was used to carry out an experimental study on desulfurization and denitrification. The effects of the packing type, packing height, spray density, mass fraction of the NaOH solution, discharge power in the DBD reactor, and simulated flue gas flow rate on the desulfurization and denitrification efficiency were analyzed, along with the influence weight of each factor, using orthogonal testing. The experimental results showed that SO2 was easily absorbed by the scrubbing solution, while the desulfurization efficiency remained at a high level (97–100%) during the experiment. The denitration efficiency was between 12 and 96% under various operating conditions. Denitration is the key problem in this system. The influence weights of the DBD power, simulated flue gas flow rate, mass fraction of the NaOH solution, spray density, packing type, and packing height on the denitration efficiency were 56.96%, 18.02%, 11.52%, 5.02%, 4.33%, and 4.16%, respectively. This paper can provide guidance to optimize the desulfurization and denitrification efficiency of this DBD reactor combined with a wet scrubbing system.

Chlorobenzene Removal Using DBD Coupled with CuO/γ-Al2O3 Catalyst

The removal of chlorobenzene using a dielectric barrier discharge (DBD) reactor coupled with CuO/γ-Al2O3 catalysts was investigated in this paper. The coupling of CuO enhanced the chlorobenzene degradation and complete oxidation ability of the DBD reactor, especially under low voltage conditions. The characterization of catalyst was carried out to understand the interaction between catalyst and plasma discharge. The effects of flow rate and discharge power on the degradation of chlorobenzene and the interaction between these parameters were analyzed using the response surface model (RSM). The analysis of variance was applied to evaluate the significance of the independent variables and their interactions. The results show that the interactions between flow rate and discharge power are not negligible for the degradation of chlorobenzene. Moreover, based on the analysis of byproducts, 4-chlorophenol was discriminated as the important intermediate of chlorobenzene degradation, and the speculative decomposition mechanism of chlorobenzene is explored.

Dielectric Barrier Discharge Reactor for the Removal of NOx From Automotive Exhaust

In this study, a self-made wire-cylinder dielectric barrier discharge (DBD) reactor was used to remove NOx. The influence of electrical and gas parameters (e.g. structure, voltage, and frequency) and temperature on the NOx removal rate was studied systematically while operating the DBD reactor with a high-voltage positive–negative double pulse power supply. The experimental results showed that following conditions led to the optimal NO conversion rate and NOx removal rate: voltage of ±12 kV, pulse frequency up to 60 Hz, oxygen concentration at 6%, reaction temperature at 300°C, and C2H2:NOx ratio at 1.5. Under these conditions, the NO conversion rate and NOx removal rate reached the highest levels of 76.4% and 31.2%, respectively. Additionally, when the process was run in conjunction with a La0.7 Sr0.3 Ni0.5 Mn0.2 Fe0.3 O3 catalyst, the reactor efficiency increased markedly, and the NO conversion and NOx removal rates increased to 94.93% and 74.97%, respectively. The findings of this study demonstrate that DBD reactor technology shows promise for the removal of NOx from automotive waste streams.