Dry Reforming of Methane with Carbon Dioxide Using Pulsed DC Arc Plasma at Atmospheric Pressure

Dry reforming of CH₄ with CO₂ to produce syngas was investigated in a plasma reactor without catalysts at atmospheric pressure. The reactants passed through the plasma zone and reacted in milliseconds with high conversions and selectivity due to the localized high temperature. The results showed that both conversions and selectivity were higher when using a DC arc discharge than using a pulsed DC arc. Increasing the input energy density promoted the conversions of reactants. At an input power of 204 W, the conversions of CO₂ and CH₄ reached 99.3 and 99.6%, respectively, and the selectivity to products was almost 100%, where the molar ratio of CO₂/CH₄ was 1 with the reactants flow rate of 100 ml/min. Very little coke was formed during the course of reaction. Key parameters such as the pulse frequency, the input power and the total feed flow rate were studied to find the optimum operating condition.     

Ashing of Organic Compounds with Spray-Type Plasma Reactor at Atmospheric Pressure

We examined the ashing treatment at atmospheric pressure by means of three spray-type reactors fed with O₂/He or O₂/Ar mixture gases. These differed in the size or the shape of their nozzles. Such reactors were able to ash an organic compound (OFPR-800; a photoresist) even at atmospheric pressure. The results showed that the following procedures are important for increasing the ashing rate: to make the gas speed after blowing out fast; to decrease the O₂ content while increasing the gas speed; and to use a gas mixture which has a slow decay rate of the active species, such as the oxygen radicals. Especially, when we used O₂/Ar mixture gas for the ashing treatment, the ashing rate became quite fast and was as fast as that of a general low pressure glow plasma.     

大尺寸大气压空气等离子体射流设备研究

本文提出了一种特殊的大尺寸大气压空气等离子体射流设备。该设备采用一种高分子耐高温涂料作为介质进行放电,通过气体渐扩通道,产生大尺寸空气等离子体射流,射流直径最宽处可以达到28mm,长度可以达到数十mm。本文对射流中的活性物质进行光谱测量,同时对射流宏观温度进行测量,指出该射流温度非常接近室温,可以用于温度敏感材料的表面处理等方面。     

Continuous Laminaribiose Production Using an Immobilized Bienzymatic System in a Packed Bed Reactor

The first continuous production system of laminaribiose from sucrose and glucose in a bienzymatic reaction is reported in this study. Immobilized laminaribiose phosphorylase and sucrose phosphorylase were used in a packed bed reactor system comprising of a 3-cm glass column at 35 °C with a steady feeding flow rate of 0.1 ml/min. Factors affecting product formation including enzyme ratio, peal concept (both enzymes in one pearl or in separate pearls), and pearl size were studied. An enzyme ratio of 2:1 of laminaribiose phosphorylase (LP) to sucrose phosphorylase (SP) when encapsulated separately in bigger size peals resulted in higher concentration of product. Laminaribiose (0.4 g/(L h)) is produced in the optimized system at steady state. The reaction system proved to be operationally stable throughout 10 days of continuous processing. A half-life time of more than 9 days was observed for both biocatalysts.     

气态污染物氯化氰的分光光度法测定

探索了氯化氰（CNCI）气体在不同介质中的稳定性和可吸收性,及光度测定条件,方法用于三聚氯氰工厂烟道气、车间空气及厂区空气中CNCI含量的测定。 结果满意。     

固定床反应器电合成乙醛酸的研究

以过饱和草酸水溶液为阴极液 ,盐酸为阳极液 ,在固定床电解槽中草酸电还原得到乙醛酸 .考察改变固定床的结构、电解温度及电流密度对生成乙醛酸电流效率和产率的影响 .结果表明 ,以铅粒作阴极 ,石墨板作阳极 ,电流密度 96 .3A·m- 2 ,阴极液空速 0 .5 0 5m·s- 1,电解温度 32℃时 ,在固定床双阳极室内反应 4 5min ,乙醛酸的电流效率仍达到 6 6 .2 % ,浓度 2 .0 2 %     

Oxidation of Dilute Benzene in an Alumina Hybrid Plasma Reactor at Atmospheric Pressure

The combination of plasma discharge and adsorption was examined for oxidation of dilute benzene in air in a plasma reactor packed with a mixture of BaTiO ₃ pellets and porous Al ₂ O ₃ pellets (i.e., an alumina hybrid reactor). The oxidative decomposition of benzene was enhanced by the benzene concentrating on the Al ₂ O ₃ pellets. Furthermore, there was a higher selectivity to CO ₂ in the products from the hybrid than from a plasma reactor packed with BaTiO ₃ pellets alone. The presence of the Al ₂ O ₃ pellets suppressed the formation of N ₂ O.     

Nonthermal Atmospheric Pressure Plasma for Methylene Blue Dye Decolorization by Using Slug Flow Reactor System

Plasma Chemistry and Plasma Processing - Non-equilibrium pulsed discharge plasma using a gas–liquid slug flow in a glass column as a plasma reactor is developed and applied to methylene blue...     

Decomposition of Acetaldehyde in Atmospheric Pressure Filamentary Nitrogen Plasma

The removal of 500?ppm acetaldehyde in nitrogen at 1?bar is characterized in a pulse dielectric barrier discharge generating a spatial random distribution of plasma filaments. The identification and the quantification of numerous by-products are performed. At 20?°C, CH₃CHO is efficiently dissociated, probably owing to quenching of N₂ metastable states. The most abundant by-products are CO, H₂, and CH₄, in consistency with the three important exit channels for the quenching of the N₂(A³?? _u ⁺ ) state by CH₃CHO proposed by Faider et al. (2011). In order of importance, other products are HCN, C₂H₆, CH₃CN, HNCO, CO₂, CH₃COCH₃, C₂H₄, C₂H₅CN, NH₃, C₂H₂, and a group of nitriles and of ketones. An increase of the temperature from 20?°C up to 300?°C induces a strong decrease of the removal characteristic energy, but the by-products types remain unchanged. Probably the reaction of H with CH₃CHO plays a role in the removal of the molecule at 300?°C.     

Nitrogen Fixation as NOx Enabled by a Three-Level Coupled Rotating Electrodes Air Plasma at Atmospheric Pressure

In this paper, a three-level coupled rotating electrodes air plasma at atmospheric pressure is developed for evaluation of nitrogen fixation. Factors influencing the NO_x production rate and energy cost, including airflow rate, the input H₂O concentration, blade numbers at each rotating electrode and rotating speed, are examined. Air flow rates prove to have no effect on the rotational temperature of N₂ 337.1 nm and the emission intensities of N₂⁺ and N₂, but specific energy input (SEI) and species’ residence time can be shorter with higher air flow rates, resulting in lower NO_x concentration and energy cost. The addition of H₂O also has a positive effect on both NO_x concentration and energy cost. Optical emission spectrum (OES) shows that air?+?H₂O plasma has stronger 336 nm (NH) and 309 nm (OH) emission lines than air plasma, suggests NH and OH are the key species in NO_x enhancement. The most energy efficient conditions are found at airflow rate of 15 l min^?1, 12% H₂O concentration, with 4 blades on each rotating speed. Under these conditions, the lowest energy cost is observed to be 165 GJ/tN.

     

苯在固定床反应器内电解制备对苯二醌

苯在固定电化学反应氧制备对苯二醌，阳极和阴极分别为多孔铅合金和铅粒。是解液是１ｍｏｌ／ｌ硫酸水溶液，苯分散于电解液中。最佳电解条件：电解液流速ｕ＝０．１９ｍ．ｓ＾－１，反应器厚度Ｌ＝１０ｍｍ，电极电位Ｅ＝１．６Ｖ，电流Ｉ＝１０Ａ和苯含量ＣＢ＝２４％，电流效率ＣＥ是６２．９％。     

Decomposition of Benzene in Air in a Plasma Reactor: Effect of Reactor Type and Operating Conditions

The decomposition of benzene was carried out in two types of plasma reactors packed with BaTiO₃ pellets: one reactor had two stainless steel electrodes (SUS reactor), and the other reactor had a glass layer between two concentric electrodes (GL reactor). The decomposition efficiency and the suppression of formation of N₂O and NO_x were greater in the GL reactor than in the SUS reactor. In contrast, the suppression of O₃ formation and the oxidation to CO_x in the SUS reactor were superior to those in the GL reactor. The effect of wa eform and frequency of applied ac power was in estigated for each reactor.     

Anaerobic Digestion of Sugarcane Vinasse Through a Methanogenic UASB Reactor Followed by a Packed Bed Reactor

The anaerobic treatment of raw vinasse in a combined system consisting in two methanogenic reactors, up-flow anaerobic sludge blanket (UASB) + anaerobic packed bed reactors (APBR), was evaluated. The organic loading rate (OLR) was varied, and the best condition for the combined system was 12.5 kg COD m^?3day^?1 with averages of 0.289 m³ CH₄ kg COD r^?1for the UASB reactor and 4.4 kg COD m^?3day^?1 with 0.207 m³ CH₄ kg COD r^?1 for APBR. The OLR played a major role in the emission of H₂S conducting to relatively stable quality of biogas emitted from the APBR, with H₂S concentrations <10 mg L^?1. The importance of the sulphate to COD ratio was demonstrated as a result of the low biogas quality recorded at the lowest ratio. It was possible to develop a proper anaerobic digestion of raw vinasse through the combined system with COD removal efficiency of 86.7% and higher CH₄ and a lower H₂S content in biogas.     

Investigation of CO2 Splitting Process Under Atmospheric Pressure Using Multi-electrode Cylindrical DBD Plasma Reactor

Plasma Chemistry and Plasma Processing - In this paper, the CO2 splitting process was performed under atmospheric pressure in a multi-electrode cylindrical dielectric barrier discharge (DBD) plasma...     

Synthesis of Ozone at Atmospheric Pressure by a Quenched Induction-Coupled Plasma Torch

The technical feasibility of using an induction-coupled plasma (ICP) torch to synthesize ozone at atmospheric pressure is explored. Ozone concentrations up to ~250 ppm were achieved using a thermal plasma reactor system based on an ICP torch operating at 2.5 MHz and ~11 kVA with an argon/oxygen mixture as the plasma-forming gas. The corresponding production rate and yield were ~20 g ozone/hr and ~2g ozone/kWh, respectively. A gaseous oxygen quench formed ozone by rapid mixing of molecular oxygen with atomic oxygen produced by the torch. The ozone concentration in the reaction chamber was measured by Fourier Transform infrared (FTIR) spectroscopy over a wide range of experimental conditions and configurations. The geometry of the quench gas flow, the quench flow velocity, and the quench flow rate played important roles in determining the ozone concentration. The ozone concentration was sensitive to the torch RF power, but was insensitive to the torch gas flow rates. These observations are interpreted within the framework of a simple model of ozone synthesis.     

Effect of Water Vapor on Benzene Decomposition Using a Nonthermal-Discharge Plasma Reactor

The effect of water vapor on benzene decomposition in air was investigatedusing a nonthermal-discharge plasma reactor packed with ferroelectricmaterials. The conversion of benzene was found to decrease with an increaseof water concentration. On the other hand, the selectivity to CO₂ in thedecomposition products increased with an increase of water concentration. Acomparison between the benzene conversion to CO and CO₂ suggested that COformation was suppressed by water to a greater extent than was CO₂formation. N₂O formation also decreased with an increase of waterconcentration. These results suggest that the activity of oxygen speciesresponsible for the formation of CO and N₂O is reduced by water.     

Influence of a Gas Injection Direction on the Reforming Performance in a Bipolar Pulse-Driven Plasma Reactor Operating at Atmospheric Pressure

Hydrogen production from methane reforming using the partial oxidation reaction is carried out using a bipolar pulse-driven plasma reactor operating at atmospheric pressure. The influence of axial and radial injections of CH₄ and O₂ on the reforming performance is investigated in conjunction with the spatial distribution of their spectral emissions by varying the O₂/C ratio at a fixed discharge power. With increasing the O₂/C ratio, the axial injection achieves the better conversion and efficiency. The measurement of spectral emissions reveals that the higher efficiency of axial injection is caused by its efficient use of oxidation reaction heat.     

Hydrogen Production from Methane Decomposition Using a Mobile and Elongating Arc Plasma Reactor

Plasma Chemistry and Plasma Processing - Hydrogen and solid carbon were produced through methane decomposition in a plasma reactor with a parallel set of screw type helix and rod-like electrodes....     

Surface Functionalization at Atmospheric Pressure by DBD-Based Pulsed Plasma Polymerization

Dielectric barrier discharge (DBD)-based plasma deposition at atmospheric pressure, using glycidyl methacrylate (GMA, methacrylic acid-[2,3-epoxy-propyl ester]) as a prototype precursor was investigated in order to evaluate the applicability of dielectric barrier discharges to obtain plasma polymers with a high degree of structural retention of the starting precursor. Using pulsed excitation of the discharge, up to about 90% of the epoxy groups of GMA can be retained in plasma polymers obtainableat deposition rates in the order of 3–5nm/s. Preliminary investigations of the mechanism of film formation under pulsed plasma conditions indicate that the reaction of intact monomer molecules withsurface radicals generated during the pulses play a prominent role.     

旋转填料床与导流板式塔组合反应器制备对羟基苯甲醛

采用旋转填料床与导流板式塔组合反应器研究了对氨基苯甲醛重氮盐的水解反应,考察了水解温度、转子转速、停留时间等参数对主产物对羟基苯甲醛收率的影响.与传统釜式水解法相比,本法将反应时间由2～3.5h缩短为3～5min,主产物收率由55%提高至82%,显著提高了生产效率,强化了生产过程.