Wire-cylinder Configuration Research Articles

Devulcanization of ground tire rubber using a plasma-assisted fluidized-bed system

The disposal of ground tire rubber (GTR) poses a significant environmental threat, necessitating the development of sustainable regeneration strategies. As an attractive alternative to traditional recycling techniques, plasma-based method is being actively explored for GTR devulcanization. To address the critical issue of poor contact between rubber and reactive species in plasma fixed-bed reactor, a novel plasma fluidized-bed system based on wire-cylinder configuration is designed and employed to regenerate GTR in this work. The results demonstrate that plasma treatment effectively breaks C-S and S-S bonds within the rubber matrix, indicative of partial de-crosslinking of the network structure. This structural alteration is manifested in a decreased crosslinking density, facilitating the partial restoration of flowability in the regenerated GTR. Notably, after 30 min of plasma treatment, the tensile strength of regenerated rubber increased significantly from 6.4 MPa to 9.4 MPa, and the elongation at break rose from 362 % to 390 %, thereby satisfying the performance requirements of superior-grade rubber materials. An underlying plasma devulcanization mechanism is proposed through a comprehensive analysis that integrates both experimental data and characterization results. The developed plasma fluidized-bed system offers an eco-friendly method for GTR devulcanization, holding significant potential to contribute to environmental sustainability and bolster circular economy efforts.

Numerical investigation of the role of linear and nonlinear forces in determining the direction of electric wind caused by atmospheric pressure DC corona discharge

In this study, the force generated by atmospheric positive and negative corona discharges was investigated using a simulation of a wire–cylinder configuration. We provided new insight into the atmospheric corona discharge by introducing a nonlinear force on the charged particles in the vicinity of the wire electrode. To elucidate the origin of both forces in corona discharges, we performed 2D simulations via COMSOL Multiphysics and MATLAB software. It was observed that the direction of nonlinear force is always from the wire to the cylinder regardless of the applied voltage polarity. It was illustrated that the corresponding nonlinear force of the positive corona is larger than that of the negative corona discharge. However, the span of the nonlinear force is greater in the negative corona discharge. The numerical simulation results showed that, in addition to the linear force (Coulomb force), a strong nonlinear force is generated around the wire electrode (powered electrode) that plays a complementary role in the production of electric wind caused by corona discharge. As this nonlinear force is limited to the vicinity of the wire electrode, it is possible to ignore the nonlinear force with a good approximation in the calculation of the total electrohydrodynamic force, but this force cannot be ignored in the process of forming the electric wind.

PHENOL WASTE TREATMENT USING OZONE-PLASMA HYBRID REACTOR

Phenol is one of the most dangerous ingredients in industrial wastewater, which has acute toxicity and is difficult to degrade in the environment. Therefore, Ozone-Plasma Hybrid Reactor (RHOP) is an effective phenol waste treatment used to test the performance of the treatment of synthetic phenolic compounds. Its working principle is based on the combination of ozonation reaction in the liquid plasma field of the reactor. Ozone as a reagent is produced by the ozonator, which is fed into the RHOP by mixing it with the liquid phase feed in the injector to enable the intensive the reaction of the two-phase mixture react. Furthermore, the two-phase mixture intensifies hydroxyl radicals when the liquid phase is in alkaline condition and continuously exposed in plasma. The results obtained from the performance test carried out on several wastes with high concentrations, showed that the system needed improvement. The improvements were made by changing the reactor system to Dielectric Barrier Discharge (DBD) plasma with wire cylinder configuration, to degrade synthetic waste containing phenolic compounds through active species formed in the reactor. This process has a high oxidation potential and decomposes various organic pollutants in waste. Furthermore, the ozonation technique was applied to the DBD reactor with the aim of increasing the amount of ozone and OH• radicals, therefore maximizing the phenol degradation process.

Characteristics of negative DC discharge in a wire-cylinder configuration under coal pyrolysis gas components at high temperatures.

This work aims to provide a comprehensive understanding of negative DC discharge under coal pyrolysis gas components (CO2, H2, N2, CH4, CO) and air. The characteristics of negative DC discharge were studied in a wire–cylinder configuration at an ambient temperature range of 20–600 °C by analyzing V–I characteristics, discharge photographs, and gas composition. With increasing temperature, corona onset voltage, spark breakdown voltage and operational voltage range for corona discharge decrease, but discharge current and electron current ratio increase. Discharge current of CO2 is higher than that of air due to the difference of electronegativity. During CO2 discharge, with the increase of output voltage, three types of discharge are successively observed, namely corona, glow and arc. However, during H2 discharge, only glow discharge is observed. Temperatures significantly affect the capability of CO to attach electrons. The discharge characteristic of CO is similar to the electronegative gas media at 20 °C and the non-electronegative gas media when the temperature exceeds 350 °C. Chemical reactions and carbon generation are observed during the CH4 and CO discharge process. The product of carbon filaments under the CH4 gas medium leads to discharge current volatility and short circuit. These results assist in understanding the property of ESP at high temperatures.

An experimental investigation of electrostatic precipitation in a wire–cylinder configuration at high temperatures

High-temperature electrostatic precipitation is a potentially convenient method for hot gas clean-up. This paper reports the characteristics of electrostatic precipitation in a wire–cylinder configuration for a temperature range of 350°C to 700°C. Three parameters, i.e., particle collection efficiency, energy consumption index and the outlet mass concentration of particles, are investigated to evaluate the comprehensive performance of an electrostatic precipitator at high temperatures and to propose a method to choose an optimum combination of the operation parameters for different conditions. The collection efficiency can be greater than 0.996 when the gas temperature is 350–700°C and the inlet mass concentration of particles is 200–3600mg/Nm3. When the voltage applied to the two electrodes is high enough (greater than 15,900V in this work), the collection efficiency is hardly influenced by the inlet mass concentrations of particles in the testing range. For example, at 620°C when the applied voltage is 15,925V, the fluctuations of the collection efficiency are within ~0.2% even if the inlet mass concentration increases ~10 times. For a given inlet mass concentration of particles, the collection efficiency increases rapidly as the applied voltage increases from the first stage to the second stage, while the collection efficiency increases slowly as the applied voltage increases from the second stage to the third stage. The relationship between the energy consumption index, the applied voltage and the inlet mass concentration of particles is given by φ=CUp2(Up−Uc)/min. As the temperature increases from 350°C to 700°C, the value of C increases from 1.0×10−5 to 3.2×10−5 and the value of Uc decreases from 20,860 to 12,503. The electric energy consumed by an electrostatic precipitator increases rapidly with the increase in the temperature.

Current analysis of DC negative corona discharge in a wire-cylinder configuration at high ambient temperatures

Abstract To study the characteristics of DC negative corona discharge in a wire-cylinder configuration at an ambient temperature range of 350–850 °C, the I – V characteristics and the current composition are analyzed under different conditions. A simple method is proposed to determine the DC corona onset threshold voltage. At high ambient temperatures, in the DC negative corona discharge gap, some electrons are not attached to the electronegative gas molecules and move to the anode tube. Thus, these electrons form an electron current, which may account for most of the total discharging current. The ratio of the electron current to the total discharging current increases with increasing temperature. In a mixture of O 2 and N 2 and a mixture of CO 2 and N 2 , the ratio of electron current increases with increasing N 2 content in the mixtures. The cathode material has little influence on the corona discharge characteristics at high ambient temperatures.

Characteristics of DC discharge in a wire-cylinder configuration at high ambient temperatures

Abstract In the present work, the characteristics of direct-current (DC) discharge in a wire-cylinder configuration at an ambient temperature range of 350–850 °C were studied by analyzing photographs of the discharging process and the corresponding V – I characteristics, with the aim of facilitating the application of plasma technology in the fields of energy and the environment. The influences of the ambient temperature, the inter-electrode gap, the gas medium and the cathode material on the DC discharge were investigated. The corona-onset threshold voltage (COTV) and the spark-breakdown threshold voltage (SBTV) decrease as the ambient temperature increases, and the SBTV decreases more rapidly. Increasing the inter-electrode gap enlarges the difference between the SBTV and the COTV. After spark breakdown, in an air atmosphere, glow discharge is more likely to take place under conditions of high ambient temperatures or small inter-electrode gaps. The values of the SBTV in different atmospheres have the following relation: air ≈ O 2 > CO 2 . At an ambient temperature range of 350–850 °C and in an atmosphere of N 2 , glow discharge and arc discharge occur successively as the output voltage of the power supply is increased, while in an atmosphere of O 2 and CO 2 , only corona and arc discharge are successively observed. In an air atmosphere, when the inter-electrode gap is 29 mm, corona, glow and arc discharge occur successively with increasing output voltage when the ambient temperature is 850 °C, while only corona and arc discharge appear when the temperature is 350–750 °C. When the inter-electrode gap is 5 mm in an air atmosphere, corona, glow and arc discharge occur successively in an ambient temperature range of 350–850 °C. The cathode material has a minor influence on the COTV and a more significant influence on the SBTV. In a device using a cathode with a low work function, the SBTV is low, and the power to maintain arc discharge is small.

Influence of ozone on the combustion of n-heptane in a HCCI engine

Homogeneous charge compression ignition (HCCI) experiments were performed in a single-cylinder diesel engine fueled with n-heptane at constant equivalence ratio of 0.3, intake temperature of 300K, and engine speed of 1500rpm. The intake manifold was seeded by ozone produced by a dielectric barrier discharge reactor with a wire–cylinder configuration. Experimental results showed that low ozone concentrations, i.e., <50ppm, have an important impact on the phasing of the cool and main flame in the engine. To interpret the engine results, the modeling of constant volume combustion at 20 and 40bars was performed using a detailed chemical kinetic reaction mechanism. The kinetic modeling indicated that the fuel starts to oxidize via reaction with O-atoms produced by ozone decomposition (n-C7H16+O→C7H15+OH) and that the ozone-accelerated production of OH speed up both cool and main flame. The production of O-atoms by decomposition of ozone during the compression stroke could be a way to control, cycle to cycle, two stage ignition fuels of HCCI engine.

Research on Electrical Characteristics of Dielectric Barrier Discharge and Dielectric Barrier Corona Discharge

The dielectric barrier corona discharge (DBCD) in a wire-cylinder configuration and the dielectric barrier discharge (DBD) in a coaxial cylinder configuration are studied. The discharge current in DBD has higher pulse amplitude than in DBCD. The dissipated power and the gas gap voltage are calculated by analyzing the measured Lissajous figure. DBCD has lower gas gap breakdown voltage. The average electric field is about 10–20 kV/cm in gas gap during DBCD, and is 30–40 kV/cm during DBD. In the positive half cycle the DBCD appears as continuous discharge current mode and in negative half cycle it appears as Trichel pulse mode. Under some conditions DBCD can show homogeneous diffuse discharges mode.

$\hbox{NO}_{3}^{-}$ Reduction for $\hbox{NO}_{\rm x}$ Removal Using Wet-Type Plasma Reactor

The fundamental characteristics of flue gas cleaning for NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> using a wet-type plasma reactor are evaluated, with attention being laid on concentrations of nitrate and ammonium ions in the liquid. The wet-type plasma reactor of the wire-cylinder configuration driven by a square-wave high voltage was used. A thin liquid film was maintained on the inner wall of the reactor. In this reactor, a discharge plasma oxidizes NO to NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , and NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is dissolved into the liquid as NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> . Continuous absorption of nitrogen oxides induces saturation and acidification of the liquid, therefore inhibiting further absorption. The effect of the addition of ammonium ions (NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ) into the liquid film on the enhancement of NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> removal has been experimentally confirmed. In that case, the addition of NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> was effective for NO oxidation, as well as NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> absorption into the liquid, resulting in the increase of NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> and NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> concentrations in the liquid. With the presence of Fe <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions in the liquid exposed to the discharge plasma, a reduction of NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> to NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> takes place. The reduction of nitrate ions to ammonia raises the solution pH and ensures continuous NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> absorption. These results suggest the possibility of the continuous operation of the wet-type plasma reactor for NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> removal without excess acidification of the absorbing water. The process that is responsible for the reduction of nitrate ions into ammonium ions is of an electrochemical nature.

Experimental study on discharge characteristics and ozone generation of dielectric barrier discharge in a cylinder–cylinder reactor and a wire–cylinder reactor

The dielectric barrier discharge (DBD) reactors with a wire–cylinder configuration and a cylinder–cylinder configuration for ozone generation are investigated experimentally. The discharge characteristics of DBD in these two reactors are studied by measurement of their electrical discharge parameters and observation of their light-emission phenomena. The ozone concentration and ozone generation efficiency under different voltages are compared and discussed for both reactors. It is found that the discharge mode of DBD in the wire–cylinder reactor is different from that in the cylinder–cylinder reactor, and the ozone concentration and ozone generation efficiency depend highly on the applied voltage in both reactors.

Application of DBD and DBCD in SO2 Removal

The dielectric barrier corona discharge (DBCD) in a wire-cylinder configuration and the dielectric barrier discharge (DBD) in a coaxial cylinder configuration are studied. The discharge current in DBD has a higher pulse amplitude than in DBCD. The dissipated power and the gas-gap voltage are calculated by analyzing the measured Lissajous figure. With the increasing applied voltage, the energy utilization factor for SO2 removal increases in DBCD but decreases in DBD because of the difference in their electric field distribution. Experiments of SO2 removal show that in the absence of NH3 the energy utilization factor can reach 31 g/kWh in DBCD and 39 g/kWh in DBD.