Investigation of Cracking by Cylindrical Dielectric Barrier Discharge Reactor on the n-Hexadecane as a Model Compound (original) (raw)
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Hexadecane Cracking in a Hybrid Catalytic Pulsed Dielectric Barrier Discharge Plasma Reactor
Industrial & Engineering Chemistry Research, 2013
In the present work, cracking of a model heavy hydrocarbon (hexadecane) in a nanosecond pulsed catalytic dielectric barrier discharge (DBD) plasma reactor has been investigated. The effect of different commercial catalyst materials based on alumina, titania, and silica has been considered on the reactor performance and products distribution. The reactor performance increases significantly when the discharge zone is packed with catalyst granules. Energy efficiency and hydrogen concentration in the produced gas vary between 36.98 and 194.44 lit/kWh and 17.7% and 63.7%, respectively. The highest energy efficiency was achieved when the plasma was packed with Mo−Ni/Al 2 O 3 catalyst for 52.3 W power input. In this condition, the production rate and concentration of hydrogen have been 108.03 mL/min and 63.7%, respectively. The breakdown voltage is decreased significantly when the reactor is packed with TiO 2 based catalyst.
Chemical Engineering Journal, 2013
h i g h l i g h t s Characteristics of the nano-second pulsed DBD reactor are investigated. The influence of hydrocarbon feed chain length and carrier gas type have studied. Carbon number of hydrocarbon feed increased reactor performance significantly. The highest energy efficiency achieved when n-hexadecane is used as a feed. The absence of CO and CO 2 in the product gas is highly desirable for PEM fuel cells. g r a p h i c a l a b s t r a c t Schematic diagram of plasma cracking process.
Journal of Natural Gas Chemistry, 2006
The direct conversion of methane using a dielectric barrier discharge has been experimentally studied. Experiments with different values of flow rates and discharge voltages have been performed to investigate the effects on the conversion and reaction products both qualitatively and quantitatively. Experimental results indicate that the maximum conversion of methane has been 80% at an input flow rate of 5 ml/min and a discharge voltage of 4 kV. Experimental results also show that the optimum condition has occurred at a high discharge voltage and higher input flow rate. In terms of product distribution, a higher flow rate or shorter residence time can increase the selectivity for higher hydrocarbons. No hydrocarbon product was detected using the thermal method, except hydrogen and carbon. Increasing selectivity for ethane was found when Pt and Ru catalysts presented in the plasma reaction. Hydrogenation of acetylene in the catalyst surface could have been the reason for this phenomenon as the selectivity for acetylene in the products was decreasing.
Hydrogen production by reforming of hydrocarbons and alcohols in a dielectric barrier discharge
Journal of Power Sources, 2007
This work reports about the use of plasmas to obtain hydrogen by reforming of hydrocarbons or alcohols in mixtures with CO 2 or H 2 O. The plasma is activated in a dielectric barrier discharge (DBD) reactor working at atmospheric pressure and low temperatures (i.e., about 100 • C). The reactor presents a great versatility in operation and a low manufacturing cost. Results are presented for the reforming of methane, methanol and ethanol. Methane transforms up to a 70% into CO and H 2 without formation of any kind of superior hydrocarbon. For the two alcohols 100% conversion into the same products is found for flows much higher than in the case of methane. The work reports a description of the reactor and the operational conditions of the power supply enabling the ignition of the plasma and its steady state operation.
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2005
Noncatalytic and nonoxidative conversion of methane in a dielectric barrier discharge (DBD) reactor is examined at different temperatures, gas residence times and input powers. In addition, the ratio of methane to helium as a diluant, is changed in the range of 0.6 to 1.8. Results show significant synergetic effects of plasma, temperature and helium on the methane conversion and C 2+ selectivities. C 2 hydrocarbons are the main products (more than 70%) of the process, however, minor amounts of heavier hydrocarbons up to C 8 are formed. At an input power of 230W and gas residence time of 6 sec, when the temperature increases from 100 to 200 o C, the methane conversion enhances by 33%. In the temperature of 100-350 o C, the methane conversion passes through a maximum at CH 4 /He ratio of 1.0, at which the highest effect of the temperature is observed. In addition, at 350 o C, when the input power increases from 140 to 230W, the CH 4 conversion enhances from 20.3 to 27.0%. As the temperature increases from 100 to 350 o C, the selectivity of ethane decreases from 81.5 to 73.0%, while the selectivities of ethylene and acetylene enhances by about 40% and 270%, respectively. The frequency of effective collisions among the reactants, excited helium (He*), and free electrons (e-) seems to increase with temperature, that in turn leads to higher methane conversions and changes in products selectivities.
Chemical Engineering Journal, 2012
In this study, a nano second pulsed dielectric barrier discharge plasma reactor has been investigated for conversion of heavy naphtha. Continuous liquid hydrocarbons cracking and instant production of hydrogen and light gaseous hydrocarbons in the range of C 1-C 3 have been studied at room temperature and atmospheric pressure by using argon as a carrier gas. The effect of applied voltage, pulse frequency and inner electrode material has been examined on the quantity and quality of products. Aluminum, copper, stainless steel, iron and brass have been selected to investigate the effect of electrode material. Results show that applied voltage, pulse repetition frequency and inner electrode material, affect the energy efficiency of the plasma cracking process. Stainless steel has been selected due to its high performance among all tested materials. The highest process efficiency has been obtained at 7 kV and 18 kHz which was 79.38 l kWh −1 for 1 ml min −1 of feed injection and 24.70 W input power. In this condition, the generation rate of hydrocarbon is 22.50 ml min −1. Results indicate that the hydrocarbon product distribution during the process is ethylene C2 > C1 C3.
Dry reforming of methane using different dielectric materials and DBD plasma reactor configurations
The effect of quartz and alumina dielectric materials on the efficiency of dielectric barrier discharge (DBD) cold plasma reactor using different configurations for dry reforming of methane (DRM) has been investigated. The performance of dielectric materials was analysed at different feed ratios, gas hourly space velocity (GHSV, h À1) and specific input energy (SIE, kJ L À1). In both reactors, the main products detected were CO and H 2 with considerable amounts of C 2 H 6. Alumina reactor prevailed in performance and the maximum conversion achieved was 74% and 68% for CH 4 and CO 2, respectively at GHSV (92 h À1) feed ratio (1:1), SIE (370 J ml À1) and discharge volume (V D = 15.7 cm 3). The CO/H 2 ratio and yields were also higher in alumina than the quartz reactor under the same experimental conditions. Furthermore, different reactor configurations displayed a significant impact in the performance of DBD plasma. Increasing discharge volume (V D) enhanced the conversion and selectivity for both dielectrics. The energy efficiency (EE) was of 0.085 and 0.078 mmol kJ À1 for alumina and quartz, respectively. The high EE in alumina reactor was evidently due to higher dielectric constant, which exhibited enhancement in power dissipation, discharge energy and reactor temperature. Stability test conferred alumina DBD plasma reactor performed better than the quartz.
Chemical Engineering and Processing - Process Intensification, 2019
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Conversion of CH4 and CO2 to syngas and higher hydrocarbons using dielectric barrier discharge
Korean Journal of Chemical Engineering, 2003
The conversion of methane to syngas and other hydrocarbons in dielectric barrier discharge plasma under the presence of CO 2 was investigated. Effects of the input voltage on the conversion of methane and CO 2 and the ratio of syngas were analyzed experimentally. The results of numerical simulations showed good quantitative agreement with those of experiments.
Journal of the Energy Institute, 2021
In the present work, the decomposition of benzene as a tar model compound was studied in a gas mixture (CO2, H2, CO, and CH4) using a dielectric barrier discharge (DBD) non-thermal plasma reactor. The combined effect of temperature and power was studied to investigate the performance of the DBD reactor. The decomposition of tar compound increased from 49.9 to 2 96 % with increasing specific input energy (SIE) from 2.05-16.4 kWh/m 3. The major products were lower hydrocarbons (C2-C5) and solid residues. The higher temperature (400 o C) in the presence of plasma (40 W), decreased the conversion of tar compound from 96 to 78 %. However, the selectivity of lower hydrocarbons increases substantially to 52 %, and the formation of solid residues is significantly reduced. Hence, the problematic solid residues formation can be controlled at a higher temperature during the treatment of gasifier product gas using non-thermal plasma.