Min-Hao Yuan

Destruction of naphthalene via ozone-catalytic oxidation process over Pt/Al2O3 catalyst

This study investigated the application of ozone in conjunction with Pt/Al(2)O(3) catalysts, called ozone-catalytic oxidation (OZCO) process, to destruct gaseous naphthalene (Nap). The experiments were carried out at various constant reaction temperatures (T), space velocities (SV) and inlet concentrations of ozone (C(O3,in)). The results indicate that the required T for the effective decomposition of Nap decreases with the increase in inlet concentration of ozone (C(O3,in)) at the same conversion level of Nap (X(Nap)). Further, the values of X(Nap) and mineralization extent of Nap (M(Nap)) increase linearly with the increase of C(O3,in.) Regarding the T at X(Nap)=50% (T(50)), there is about 20K reduction at SV=100,000 h(-1) for the case of OZCO process with C(O3,in) of 1750 ppmv (T(50)=460 K) compared to the process without ozone (T(50)=480 K). Further, the power law can be applied to describe the data by using the second order expression with respect to ozone and Nap concentration. The observed activation energy and frequency factor are 68.3 kJ mol(-1) and 5.36 x 10(12)L(2)mol(-1)g(-1)-cat.s(-1), respectively. The information obtained is useful for the rational design and operation of the treatment of Nap via the OZCO process.

Atmospheric-Pressure Radio-Frequency Discharge for Degradation of Vinyl Chloride With

This study investigates the application of a radio-frequency-powered plasma with a Pt/γ-Al₂O₃ catalyst to decompose the chlorinated volatile organic compound of vinyl chloride (VC) in air. The use of an atmospheric-pressure plasma jet is explored as an innovative technology for the treatment of VC. The effects of some major system parameters such as input power (<i>P</i>_WI), plasma energy density, initial concentration of VC (<i>C</i>₀), and space velocity (SV) of the catalyst on the plateau temperature (<i>TP</i>) of a reactor and conversions of VC (<i>X</i>_VC) are studied and elucidated. The results show that the effectiveness of the plasma-assisted catalysis is evident as indicated by the increase of <i>X</i>_VC and the rate constant. At a <i>P</i>_WI of 250 W without a catalyst, the values of <i>X</i>_VC were 14% and 5.4% for <i>C</i>₀ = 200 and 450 ppmv, respectively. In the presence of the Pt/γ-Al₂O₃ catalyst with an SV of 17 400 h^-1, the values of <i>X</i>_VC for <i>C</i>₀ = 200 and 450 ppmv increased to 49% and 39%, respectively. Note that the values of <i>TP</i> were 550 K and 430 K without and with the Pt/γ-Al₂O₃ catalyst at an SV of 17 400 h^-1 and a <i>P</i>_WI of 250 W. The proposed kinetic models describe the relationships of <i>C</i>/<i>C</i>₀ with the major parameters for the plasma and plasma-assisted catalytic degradation of VC, showing good agreement with the experimental data. The information obtained is useful for the operation, design, and analysis of plasma devices.

\hbox{Pt}/\hbox{Al}_{2}\hbox{O}_{3}

This study examined the effects of additives of potassium carbonate (K2CO3) and zinc oxide (ZnO) on the pyrolysis of waste sunflower-oil cake using a 60 kW pilot-scale plasma torch reactor. The major gaseous products were CO and H2. The productions of CO and CH4 increased while that of H2 decreased with the addition of K2CO3. The use of ZnO reduced while enhanced the formation of CO and H2, respectively. In order to match the appeal of resource reutilization, one can use the waste K2CO3 resulted from the sorption of CO2 with KOH in greenhouse gas control and the waste ZnO obtained from the melting process as additives for the co-pyrolysis of sunflower-oil cake, yielding fuels rich in CO and H2, respectively.

Catalyst

Magnetic polyvinyl alcohol adsorbent M-PVAL was employed to remove and concentrate dimethyl phthalate DMP. The M-PVAL was prepared after sequential syntheses of magnetic Fe3O4 (M) and polyvinyl acetate (M-PVAC). The saturated magnetizations of M, M-PVAC, and M-PVAL are 57.2, 26.0, and 43.2 emu g−1 with superparamagnetism, respectively. The average size of M-PVAL by number is 0.75 μm in micro size. Adsorption experiments include three cases: (1) adjustment of initial pH (pH0) of solution to 5, (2) no adjustment of pH0 with value in 6.04–6.64, and (3) adjusted pH0 = 7. The corresponding saturated amounts of adsorption of unimolecular layer of Langmuir isotherm are 4.01, 5.21, and 4.22 mg g−1, respectively. Values of heterogeneity factor of Freundlich isotherm are 2.59, 2.19, and 2.59 which are greater than 1, revealing the favorable adsorption of DMP/M-PVAL system. Values of adsorption activation energy per mole of Dubinin-Radushkevich isotherm are, respectively, of low values of 7.04, 6.48, and 7.19 kJ mol−1, indicating the natural occurring of the adsorption process studied. The tiny size of adsorbent makes the adsorption take place easily while its superparamagnetism is beneficial for the separation and recovery of micro adsorbent from liquid by applying magnetic field after completion of adsorption.

Co-pyrolysis of sunflower-oil cake with potassium carbonate and zinc oxide using plasma torch to produce bio-fuels

In this study, vinyl chloride (VC), the primary material for manufacturing polyvinyl chloride (PVC), is decomposed via catalytic oxidation (C-OX) using Pt/γ-Al2O3 catalyst. The effects of related major factors such as reaction temperature (T) and gas hourly space velocity on the conversion of VC (X) were examined. The values of T for achieving conversions of 50% and 90% are 504 and 580 K with C-OX, respectively, whereas those without Pt/γ-Al2O3 (i.e., thermal oxidation, T-OX) are 900 and 983 K, respectively, thus indicating that C-OX significantly reduces T for effective oxidation of VC to form CO2, HCl, and Cl2 when compared with T-OX. The mineralizations of carbon in VC to form CO2 are 75.5% and 38% for C-OX and T-OX, respectively, at 90% X. The conversions of chlorine atom in 1,2-dichloroenane (DCEA) to Cl in HCl and Cl2 are approximately 42% and 50.8% for C-OX and T-OX, respectively, at 90% X. These results indicate that the Pt/γ-Al2O3 catalyst exhibits remarkable performance for the mineralizations to form CO2 even though a proportion of chlorine atoms are adsorbed on the Pt surface. The Eley–Rideal model can be used to describe the experimental results, thus yielding activation energy and frequency factor values of 49.0 kJ mol−1 and 1.77 × 106 s−1, respectively. The obtained information and kinetic parameters are useful for the rational design and operation of C-OX process for the abatement of VC.

Adsorption Removal of Environmental Hormones of Dimethyl Phthalate Using Novel Magnetic Adsorbent.

This paper presents the Statistical Analysis of Passive Sonar Performance Prediction in Littoral Environments. Passive sonar performance and acoustic prediction mainly refer to the detection range. The inputs for estimating the sonar detection range include the Figure of Merit (FOM), Transmission Loss (TL), and Ambient Noise (NL) of the operation region. These inputs are directly related to the ocean environment; hence, the detection range is, too. A littoral environment is highly variable both in time and space. This paper proposes a methodology for analyzing the statistical properties of the detection range from measurements of ocean water column properties. It is found that the detection range of the southwestern region of Taiwan in the summer is 13.8km with 5.9km as the standard deviation and in the winter is 37.8km with 33.6km as the standard deviation.

Catalytic destruction of vinyl chloride over an alumina–supported platinum catalyst

Abstract Plasma decompositions of n-butanol (n-b) in air over working gases of air (n-b/air with 21 vol.% O2) and Ar (nb/ air/Ar with 5 vol.% O2) were studied using an atmospheric-pressure plasma jet (APPJ) reactor with and without Pt/Al2O3 catalyst. The utilization of catalytic APPJ (CAPPJ) shows excellent performance in terms of the conversion of n-butanol in n-b/air of 94.7% and n-b/air/Ar of 99.5% at plasma energy density = 3.75 kJ L-1 and space velocity = 17,400 h-1. By comparing the working gases of air and Ar, the results indicate that n-b/air/Ar system exhibits slightly better performance than n-b/air system in APPJ and CAPPJ, suggesting that energetic primary electrons from Ar discharge would sufficiently retain the plasma reactive species for facilitating the decomposition of n-butanol. The proposed kinetic models show good agreement with the experimental data of APPJ and CAPPJ. The information obtained is useful for the operation, design and analysis of plasma system.

Statistical Analysis of Sonar Performance Prediction in Littoral Environments

Dimethyl phthalate (DMP) was treated via wet oxygen oxidation process (WOP). The decomposition efficiency η DMP of DMP and mineralization efficiency η TOC of total organic carbons were measured to evaluate the effects of operation parameters on the performance of WOP. The results revealed that reaction temperature T is the most affecting factor, with a higher T offering higher η DMP and η TOC as expected. The η DMP increases as rotating speed increases from 300 to 500 rpm with stirring enhancement of gas liquid mass transfer. However, it exhibits reduction effect at 700 rpm due to purging of dissolved oxygen by overstirring. Regarding the effects of pressure P T, a higher P T provides more oxygen for the forward reaction with DMP, while overhigh P T increases the absorption of gaseous products such as CO2 and decomposes short-chain hydrocarbon fragments back into the solution thus hindering the forward reaction. For the tested P T of 2.41 to 3.45 MPa, the results indicated that 2.41 MPa is appropriate. A longer reaction time of course gives better performance. At 500 rpm, 483 K, 2.41 MPa, and 180 min, the η DMP and η TOC are 93 and 36%, respectively.