VOCs Destruction by Plasma Catalyst Coupling Using AL-KO PURE Air Purifier on Industrial Scale

We have investigated in this study the destruction of acetone and toluene with AL-KO PURE air purifier (AL-KO PURE) on industrial scale. In the case of acetone, 100% pollutant abatement is achieved with AL-KO PURE over more than 80 hours (the test duration time) at the high level concentration of 0.5 ppm (1187 μg/m3, about 7 times higher than the average living room level). This corresponds to 0.2 μmol/s with a flow rate of 38.42 m3/h. The regeneration of a saturated catalytic filter was also tested. When the catalytic filter of AL-KO PURE is fully saturated with acetone, a 100% acetone destruction efficiency can be achieved at 0.46 ppm concentration with 25% fan speed. Moreover the second pollutant, toluene, has been also studied. 100% toluene abatement also is achieved with AL-KO PURE over more than 80 hours (the test duration time) at the high level concentration of 0.2 ppm (811 μg/m3, 0.087 μmol/s with a flow rate of 38.42 m3/h). Finally, the availability for the simultaneous removal of both pollutants, acetone and toluene, has been also studied.

Degradation of tiamulin by a packed bed dielectric barrier plasma combined with TiO_(2)catalyst

Recently,a plasma catalyst was employed to efflciently degrade antibiotic residues in the environment.In this study,the plasma generated in a packed bed dielectric barrier reactor combined with TiO_(2)catalyst is used to degrade the antibiotic tiamulin(TIA)loaded on the surface of simulated soil particles.The effects of applied voltage,composition of the working gas,gas flow rate and presence or absence of catalyst on the degradation effect were studied.It was found that plasma and catalyst can produce a synergistic effect under optimal conditions(applied voltage 25 k V,oxygen ratio 1%,gas flow rate 0.6 l min^(-1),treatment time 5 min).The degradation efflciency of the plasma combined with catalyst can reach 78.6%,which is 18.4%higher than that of plasma without catalyst.When the applied voltage is 30 k V,the gas flow rate is 1 l min^(-1),the oxygen ratio is 1%and the plasma combined with TiO_(2)catalyst treats the sample for 5 min the degradation efflciency of TIA reached 97%.It can be concluded that a higher applied voltage and longer processing times not only lead to more degradation but also result in a lower energy efflciency.Decreasing the oxygen ratio and gas flow rate could improve the degradation efflciency.The relative distribution and identity of the major TIA degradation product generated was determined by high-performance liquid chromatography–mass spectrometry analysis.The mechanism of TIA removal by plasma and TiO_(2)catalyst was analyzed,and the possible degradation path is discussed.

Synergistic removal of nitrogen monoxide by non-thermal plasma and catalyst simultaneously

An experimental system of De-NO with plasma-catalyst（Cu zeolite） was established to investigate the differences between De- NO with plasma-catalyst and De-NO only with plasma, to provide the instruction for selecting appropriate catalyst and operating condition, The characteristics of De-NO with plasma and De-NO with plasma-catalyst were investigated comparatively by experiments. The experimental results show that De-NO with plasma-catalyst has high NO removal rate; Cu zeolite is an effective catalyst which can promote NO removal rate in plasma remarkably; De-NO with plasma-catalyst should be operated at low temperature and the temperature has opposite effects on the function of catalvst and plasma; water vapor and O2 can increase the NO removal rate.

Catalyst-Packed Non-Thermal Plasma Reactor for Removal of Nitrogen Oxides

A single-stage plasma-catalytic reactor in which catalytic materials werepacked was used to remove nitrogen oxides. The packing material was scoria being made of variousmetal oxides including Al_2O_3, MgO, TiO_2, etc. Scoria was able to act not only as dielectricpellets but also as a catalyst in the presence of reducing agent such as ethylene and ammonia.Without plasma discharge, scoria did not work well as a catalyst in the temperature range of 100 ℃to 200 ℃, showing less than 10% of NOx removal efficiency. When plasma is produced inside thereactor, the NOx removal efficiency could be increased to 60% in this temperature range.

Effect of La_2O_3/γAl_2O_3 Catalyst on the Activation of CH_4 and CO_2 to C_02 Hydrocarbons under Non-equilibrium Plasma

In the reaction of methane and carbon dioxide to C2 hydrocarbons under non-equilibrium plasma, methane conversion was decreased, but selectivity of C2 hydrocarbons was increased when using La2O3/?Al2O3 as catalyst. So the yield of C2 hydrocarbons was higher than using plasma alone. The synergism of La2O3/?Al2O3 and plasma gave methane conversion of 24.9% and C2 yield of 18.1%. The distribution of C2 hydrocarbons changed when Pd- La2O3/?Al2O3 was used as catalyst, the major C2 product was ethylene.

Regeneration of C_4H_(10) dry reforming catalyst by nonthermal plasma

Carbon deposition via coke formation is one of the critical problems causing catalyst deactivation during the reforming of hydrocarbons. An effort was made to regenerate the catalyst （Ni/γ-alumina） by oxidation methods. Two approaches were carded out for the regeneration of the deactivated catalyst. The first one involves the plasma treatment of the deactivated catalyst in the presence of dry air over a temperature range of 300-500℃, while the second one only the thermal treatment in the same temperature range. The performance of the regenerated catalyst was evaluated in terms of C4H10 and CO2 conversions and the physicochemical characteristics were examined using a surface area analyzer, an elemental analyzer, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. It was observed that the carbon deposit （coke） on the catalyst was about 9.89 wt% after reforming C4H10 for 5 h at 540℃. The simple thermal treatment at 400 ℃ reduced carbon content to 6.59 wt% whereas it was decreased to 3.25 wt% by the plasma and heat combination. The specific surface area was fully restored to the original state by the plasma-assisted regeneration at 500℃. As far as the catalytic activity is concerned, the fresh and regenerated catalysts exhibited similar C4H10 and CO2 conversion efficiencies.

Non-Conventional Plasma Assisted Catalysts for Diesel Exhaust Treatment: A Case Study

This paper reports the application of pulse discharges along with catalysts in treat- ing the exhaust gas at higher temperatures. In the present work a plasma reactor, filled with catalysts, called as plasma catalytic reactor, is studied for removal of oxides of nitrogen, total hydrocarbons and carbon monoxide. The experiments are conducted on an actual diesel engine exhaust at no-load and at different temperatures starting from room temperature to 300°C. The removal efficiencies of these pollutants are studied. The experiments are carried out with both con- ventional and non-conventional catalysts. The idea is to explore the pollutant removal efficiency characteristics by non-conventional catalysts. The efficiency results are compared with that of conventional catalysts. The experiments are carried out at a constant pulse repetition rate of 120 pps. Both pellet and honeycomb type catalysts are used in the study.

Partial Oxidation of Methane with Sol-Gel Fe/Hf/YSZ Catalyst in Dielectric Barrier Discharge: Catalyst Activation by Plasma

A 1% Fe-30% Hf over yttria-stabilized zirconia catalyst in combination with novel plasma-assisted activation techniques for a direct partial oxidation of methane to methanol was tested using dielectric barrier discharge plasma at ambient temperature and atmospheric pressure. However, instead of methanol, the reaction products were dominated by HE, CO, CO2, C2, and H2O. A catalytically activated plasma process increased the production of methanol compared with a noncatalytic plasma process. The maximum selectivity of methanol production was achieved using a catalyst that was treated at higher applied power.

A design of experiments approach for the development of plasma synthesized Sn-silicate catalysts for the isomerization of glucose to fructose

The use of non-equilibrium plasmas for the synthesis of heterogeneous catalysts is a field that has not been explored intensively. The main reasons for the recent increase of research activity in this field are related to the advantages that go with the technique of plasma enhanced chemical vapor deposition （PECVD）. The most principal of these advantages are the possibility to avoid the use of environmentally harmful solvents and the one-step nature of the procedure, making it very time and labor efficient. Non-equilibrium plasma technology, more in particular dielectric barrier discharge （DBD） technology, has been applied in this work for the synthesis of hybrid tin-silicate materials to be used as a heterogeneous catalyst in the isomerization of glucose into fructose. Atomizers, innovative devices which make it possible to inject nanosized precursor liquids into the plasma zone, are used instead of applying vapor phase techniques, where the amount of precursor is limited by the vapor pressure of the liquid. A design of experiments approach has been employed to investigate the effect of the plasma parameters, namely gas flow, frequency and power density, on the catalytic properties of the catalysts within a well-defined parameter field. It has been found that indeed these parameters, together with the molar ratio of Si/Sn, have an important influence on the activity, selectivity, and thus yield of the produced chemicals.

Enhancement in Activity of a Vanadium Catalyst for the Oxidation of Sulfur Dioxide by Radio Frequency Plasma During the Preparation Process

Radio frequency plasma was used to prepare a vanadium catalyst. The resultsshowed that activating time of the catalyst could be shortened quickly and the catalytic activitywas improved to some extent with the use of plasma. Catalyst Ls-9 was prepared under an optimalcondition of 40 W discharge power, 10 min discharge time and 8 Pa gas pressure. The catalyticactivity was up to 54.7% at 410℃, which was 2.2% higher than that of the Ls-8 catalyst. Only 10 minwas needed to activate the catalyst with plasma, which was 1/9 of the traditional calcination time.For Ls-9, both the endothermic as well as the exothermic peaks detected by differential thermalanalysis shifted to higher temperatures obviously, indicating that its crystal phase could melteasily. There existed an apparent endothermic peak at 283℃. SEM photographs showed a uniform sizedistribution. It is inferred that the quadrivalent vanadium compound may exist mainly in the form ofVOSO_4.

Synergism of Plasma and Catalyst on the Dehydrogenative Coupling of Methane

At atmospheric pressure and ambient temperature, pulse corona induced plasma was used as a new method for dehydrogenative coupling of methane. The synergism of plasma and catalyst on dehydrogenative coupling of methane was investigated. Experimental results have revealed that the synergism does exist, when positive corona within a suitable power range and an intermediate pulse repetition frequency (PRF) for a loaded 7-Mn2O3/7-A12O3 catalyst were chosen. In respect to the mechanism approach, a tentative model for general pathway was proposed to explain the role of plasma and catalyst partaking in the process of methane decomposition and C2 products formation.

Ni-Co/Mg-Al catalyst derived from hydrotalcite-like compound prepared by plasma for dry reforming of methane

Ni-Co bimetallic catalysts with different Ni/Co content were derived from cold plasma jet decomposition and reduction of hydrotalcite-like compounds containing Ni,Co,Mg and Al,and their catalytic performance was investigated with dry reforming of methane.Experimental results showed that the hydrotalcite-like precursors could be completely decomposed and partly reduced by cold plasma jet,and the Nicontained catalysts exhibited much higher activity than the catalyst without Ni.Especially,the catalyst with Ni/Co ratio of 8/2 achieved not only the highest conversions of 80.3%and 69.3%for CH4 and CO2,respectively,but also the best stability in 100 h testing.The catalysts were characterized by XRD,XPS,TEM and N2 adsorption techniques,and the results showed that the better performance of the 8Ni2Co bimetallic catalyst was attributed to its higher metal dispersion,smaller metal particle size,as well as the interaction effect between Ni and Co,which were brought by the special catalyst preparation method.

Simultaneous Oxidization of NO_x and SO_2 by a New Non-thermal Plasma Reactor Enhanced by Catalyst and Additive

The non-thermal plasma as one of the most promising technologies for removing NOx and SO2 has attrm^ted much attention. In this study, a new plasma reactor combined with catalyst and additive was developed to effectively oxidize and remove NOx and SO2 in the flue gas. The experimental results showed that TiO2 could improve the oxidation efficiency of SO2 in the case of applying plasma while having a negative effect on the oxidation process of NO and NOx. With the addition of NH3, the oxidation rates of NOx, NO and SO2 were slightly increased. However, the effect of adding NH3 on NOx oxidation was negative when the temperature was above 200℃.

Preparation of novel Ni-Ir/γ-Al_2O_3 catalyst via high-frequency cold plasma direct reduction process

The novel Ni-Ir/γ-Al2O3 catalyst, denoted as NIA-P, was prepared by high-frequency cold plasma direct reduction method under ambient conditions without thermal treatment, and the conventional sample, denoted as NIA-CR, was prepared by impregnation, thermal calcination, and then by H2 reduction method. The effects of reduction methods on the catalysts for ammonia decomposition were studied, and they were characterized by XRD, N2 adsorption, XPS, and H2-TPD. It was found that the plasma-reduced NIA-P sample showed a better catalytic performance, over which ammonia conversion was 68.9%, at T = 450℃, P = 1 atm, and GHSV = 30, 000 h^-1. It was 31.7% higher than that of the conventional NIA-CR sample. XRD results showed that the crystallite size decreased for the sample with plasma reduction, and the dispersion of active components was improved. There were more active components on the surface of the NIA-P sample from the XPS results. This effect resulted in the higher activity for decomposition of ammonia. Meanwhile, the plasma process significantly decreased the time of preparing catalyst.

Oxygen-Free Conversion of Methane to Ethylene in a Plasma-Followed-by-Catalyst (PFC) Reactor

Oxygen-free conversion of methane to ethylene was investigated in a two-stage plasma-followed-by-catalyst （PFC） reactor. In the absence of catalyst, pulsed spark discharges and pulsed corona discharges were compared for methane conversion. The results showed that methane was mainly converted to acetylene, but pulsed spark discharges exhibited distinct advantages over the pulsed corona discharges in methane conversion. Thereby, pulsed spark discharges were employed and followed by Ag-Pd/SiO2 catalyst for achieving ethylene as a target product in the PFC reactor. Using the PFC reactor, a steady single-pass ethylene yield of 57% was obtained at a rate of methane conversion of 74%.

Methane Coupling Using Hydrogen Plasma and Pt/γ-Al_2O_3 Catalyst

In this paper, methane coupling at ambient temperature, under atmospheric pressure and in the presence of hydrogen was firstly investigated by using pulse corona plasma and Pt/g-Al2O3 catalyst. Experimental results showed that Pt/g-Al2O3 catalyst has catalytic activity for methane coupling to C2H4. Over sixty percent of outcomes of C2 hydrocarbons were detected to be ethylene.

Investigation on Interaction between Cold Plasma with Catalysts

The characteristic parameters were measured with floating double probe method when cold plasma was interacting with catalysts, such as MoO3/Al2O3, NiY, Pd/Al2O3, which were used in the conversion of natural gas to C2 hydrocarbons through electrical field enhanced plasma catalysis. These parameters were compared in different input voltage, different atmosphere, before and after reaction in plasma field. The interaction between catalysts and cold plasma was also investigated. This confirm that cold plasma can enhanced catalysis effect.

Dry reforming of methane on active and coke resistant Ni/Y_2Zr_2O_7 catalysts treated by dielectric barrier discharge plasma

In this study, Ni/YZrOcatalysts prepared with impregnation method and treated by dielectric barrier discharge plasma(DBD) in different atmospheres have been investigated for methane dry reforming. It is revealed by H-TPR that plasma treatment can enhance the interaction between Ni O/Ni particles and the YZrOpyrochlore support. Therefore, catalysts with smaller Ni O and Ni grains sizes, higher metallic Ni active surface areas can be achieved, as evidenced by XRD, TEM and Hadsorption-desorption measurements. As a consequence, the plasma-treated catalysts show significantly improved activity, stability and coke resistance, as testified by the TEM and TGA-DSC results. Plasma treatment in H/Ar gas mixture is found to be the best condition to prepare Ni/YZrO, which can be used to obtain a catalyst with the highest activity, stability and most potent coke resistance. It is believed that the smaller Ni grain size and higher metallic Ni active surface area induced by plasma treatment are the inherent reasons accounting for the promoted reaction performance of the Ni/YZrOpyrochlore catalysts.

Plasma-chemical Synthesis and Regeneration of Catalysts for CH_4 Steam Conversion

We carried out experimental studies concerning the plasma-chemicalsynthesis(PCS) of a catalyst for CH_4 steam conversion and designed and built the equipment for PCSand/ or regeneration of spent catalyst for CH_4 steam conversion. Under the conditions of anelectric-arc low-temperature plasma (LTP), we studied the Ni-O-Al system and performed acomprehensive physicochemical analysis of the ultradispersed product obtained. It's the first timeworldwide when the conditions of plasma-chemical synthesis and/ or regeneration of CH_4 steamconversion catalysts under the conditions of electric-arc LTP are investigated depending on theplasma-chemical process (PCP) parameters and the plasma-chemical reactor (PCP) type (with CW-'coldwalls' T_W = 500 K or WW-'warm walls' T_W = 1500 K), samples with a specific surface of 120 m^2/gare obtained. Plasma-chemically synthesized and/ or regenerated samples have a homogenous chemicalcomposition similar to that the Girdller (USA) conventional industrial catalyst. It is empiricallyestablished that the optimal temperature range in PCR for synthesis of samples with maximumdispersity is (2000～3000) K. Results from investigation on dynamics and kinetics ofplasma-chemically synthesized and / or regenerated catalysts for CH4 steam conversion show thatunder LTP conditions premises for the formation of catalyst compositions are established. They arereduced 3 to 4 times faster than their industrial analogues. High specific surface of the samples,homogenous composition, high rate of active chemical surface formed by reduction, faulty crystallattice of catalytically active phases and mostly high catalytic activity make them a potentialcompetitor with their industrial analogues for their probable production in catalyst shops.