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Decomposition of dichloromethane (CH2Cl2) using a gliding plasma was examined and reported in this paper. The effects of initial concentrations of CH2Cl2, total gas flow rates, and input frequency have been studied to evaluate the performance of gliding arc on CH2Cl2 decomposition. Using atmospheric pressure air as the carrier gas, experimental results indicate that the maximum conversion of CH2Cl2 was 95.1% at a total gas flow rate of 180 L/hr containing 1% by volume of CH2Cl2. The reaction occurred at an exothermic condition and gaseous products are dominated by CO, CHCl3, and Cl2. CO2 and CCl4 are also detected in the product stream in small amounts. The conversion of CH2Cl2 increases with the increasing applied voltage and decreasing total gas flow rate.

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.

Plasma processing of the chloromethane compounds (methylene chloride (CH2Cl2), chloroform (CHCl3) and carbon tetrachloride (CCl4)) diluted in atmospheric air using a gliding arc has been studied. Various injected initial chloromethane concentrations, total gas flow rates and power frequencies were used as the variables to investigate the discharge characteristics. This paper evaluates the phenomenon of chloromethane processing by gliding-arc plasma.

The decomposition of the chlorinated hydrocarbons CCl4 and CHCl3 in a gliding-arc plasma was examined. The effects of initial concentrations, total gas flow rates and power consumption were investigated. The conversion of the hydrocarbons mentioned above was relatively high. It could reach 80% for CCl4 and 97% for CHCl3. In atmospheric air as a carrier gas, the reaction was exothermic, and the main products were CO2, CO and Cl2. The transformation into CCl4 was also detected for the decomposition reaction of CHCl3. The conversion of these compounds increased with increasing frequency of power supplied and decreasing total gas flow rate.

Our purpose is to identify a computational level sufficiently dependable and affordable to assess trends in the interaction of a variety of radical or closed shell unsaturated hydro-carbons A adsorbed on soot platelet models B. These systems, of environmental interest, would unavoidably have rather large sizes, thus prompting to explore in this paper the performances of relatively low-level computational methods and compare them with higher-level reference results. To this end, the interaction of three complexes between non-polar species, vinyl radical, ethyne, or ethene (A) with benzene (B) is studied, since these species, involved themselves in growth processes of polycyclic aromatic hydrocarbons (PAHs) and soot particles, are small enough to allow high-level reference calculations of the interaction energy ΔEAB. Counterpoise-corrected interaction energies ΔEAB are used at all stages. (1) Density Functional Theory (DFT) unconstrained optimizations of the A-B complexes are carried out, using the B3LYP-D, ωB97X-D, and M06-2X functionals, with six basis sets: 6-31G(d), 6-311 (2d,p), and 6-311++G(3df,3pd); aug-cc-pVDZ and aug-cc-pVTZ; N07T. (2) Then, unconstrained optimizations by Møller-Plesset second order Perturbation Theory (MP2), with each basis set, allow subsequent single point Coupled Cluster Singles Doubles and perturbative estimate of the Triples energy computations with the same basis sets [CCSD(T)//MP2]. (3) Based on an additivity assumption of (i) the estimated MP2 energy at the complete basis set limit [EMP2/CBS] and (ii) the higher-order correlation energy effects in passing from MP2 to CCSD(T) at the aug-cc-pVTZ basis set, ΔECC-MP, a CCSD(T)/CBS estimate is obtained and taken as a computational energy reference. At DFT, variations in ΔEAB with basis set are not large for the title molecules, and the three functionals perform rather satisfactorily even with rather small basis sets [6-31G(d) and N07T], exhibiting deviation from the computational reference of less than 1 kcal mol(-1). The zero-point vibrational energy corrected estimates Δ(EAB+ZPE), obtained with the three functionals and the 6-31G(d) and N07T basis sets, are compared with experimental D0 measures, when available. In particular, this comparison is finally extended to the naphthalene and coronene dimers and to three π-π associations of different PAHs (R, made by 10, 16, or 24 C atoms) and P (80 C atoms).

The decomposition of chloroform (CHCl3) diluted in air was studied. The experiment was carried out by using a gliding arc plasma. Different values of initial concentrations of chloroform, total gas flow rates, and input power frequencies have been used to investigate this effects on the conversion reaction products both qualitatively and quantitatively. Experimental results indicate that the maximum conversion of chloroform was 97% at a total gas flow rate of 180 L h−1 containing 1% chloroform. Using air as carrier gas, decomposition of CHCl3 produces CCl4, CO2, CO, and Cl2 as the main products. Small amounts of HCl and COCl2 are also detected. Liquid products were also produced.

PFAD can be utilized as raw material for producing calcium soap, a kind of ruminant feed supplement. It gives benefits to the ruminants’ health and increases the quantity and quality of cattle’s milk. This research evaluated the effect of stoichiometric mole ratio of Ca(OH)2 to PFAD and water temperature on calcium soap production using PFAD and calcium hydroxide as raw materials by applying modified fusion method. The result showed that the acid value of products decreased as the mole ratio of Ca(OH)2 to PFAD increased and the low water temperature lowered the acid value of products. The highest fatty acid conversion (98%) was achieved at the stoichiometric mole ratio of 3. However, the use of such high mole ratio is not preferable because the product will have excessive calcium, which may disturb the absorption of other minerals in ruminant’s digestion. Thus, further research related to operating condition and the use of other calcium sources in the calcium soap production is still required.

Initially developed for more than 20 years ago, the copper over zinc and aluminum oxide (ZnO/Al2O3) catalyst system is used for low-pressure methanol synthesis. Recently, the Cu/ZnO/Al2O3 (CZA) was shown to be active in a dielectric-barrier discharge (low-temperature plasma). In this paper, the investigation on the copper as the active site of the catalyst was discussed on the basis of experimental results and its characterization analysis. The catalyst was attempted to aid the reaction performance of partial oxidation of methane in order to produce methanol. All CZA-based catalysts were successful in increasing methanol selectivity, and the Cu oxide performed better than a metallic-copper catalyst.

Formation of the first ring structure from small aliphatic molecules is often regarded as the rate-determining step (and in any case as a step of paramount importance) in the combustive growth of larger aromatic systems and soot lamellae. Among possible reactions able to start off this process, the radical addition of the propargyl radical to butadiyne (diacetylene) has been recently studied theoretically [G. da Silva, A. Trevitt, Phys. Chem. Chem. Phys. 13 (2011) 8940] and shown to lead preferentially to a 5-membered ring intermediate. The same reaction is here addressed focusing instead on the possible formation of 6-membered rings. The large variety of partially intertwined reaction pathways is the basis for a subsequent RRKM study (carried out at different combustion temperatures). It confirms, on one hand, the favored formation of fulvenallenyl radical indicated by da Silva and Trevitt, but also indicates the possible formation of six-membered cyclic systems as minor products. In particular, at high pressure, six-membered ring system yields are very low, but at lower pressures a more significant yield of six-membered ring product is predicted.

The removal process of acid gases such as H2S in natural gas processing industry is required in order to meet sales gas specification. Hydrodesulfurization (HDS)is one of the processes in the refinery that is dedicated to reduce sulphur.InHDS unit, phase separator plays important role to remove H2S from hydrocarbons, operated at a certain pressure and temperature. Optimization of the number of separator performed on the system is then evaluated to understand the performance and economics. From the evaluation, it shows that all systems were able to meet the specifications of H2S in the desired product. However, one separator system resulted the highest capital and operational costs. The process of H2S removal with two separator systems showed the best performance in terms of both energy efficiency with the lowest capital and operating cost. The two separator system is then recommended as a reference in the HDS unit to process the removal of H2S from natural gas.

In liquefied natural gas (LNG) process production, one of the important units is heavy hydrocarbon removal unit to prevent freezing during liquefaction. For small scale of LNG plant, this unit is usually integrated with main heat exchanger. Feed is obtained from main heat exchanger then flows to separator to separate liquid from gas. The separator operating condition is called as Midpoint condition. Selecting Midpoint conditions have impact to light hydrocarbon losses, Specific Brake Horse Power (SBHP) process, and heating value of LNG. Hence understanding of selecting this condition and its effect to light hydrocarbon losses, SBHP process, and HHV of LNG will help to design more efficient LNG plant. According to study, the lower of Mid-Point temperature will result in lower SBHP, lower of light hydrocarbon losses, and increase LNG of HHV value. Meanwhile, the higher Mid-Point pressure will result in lower SBHP, higher light hydrocarbon losses, and lower LNG of HHV value. The change of Mid-Point pressures have more impact to light hydrocarbon losses than SBHP process.

This paper presents a decomposition study of 1,2-dichlorobenzene (DCB) using a dielectric barrier discharge (DBD). The discussion is focused on the effects of variations of carrier gases, DCB concentrations and input voltages on the decomposition performance. The DCB conversion was conducted inside a cylindrical reactor consists of silver film as the outside electrode and a spring coil as the inside electrode. Two carrier gases, i.e. air and nitrogen, were introduced to the reactor at a total flow rate of 500 mL/min with DCB concentrations of 100, 300 and 500 ppm. Gaseous products, before and after plasma treatment, were analysed by a gas chromatography and FT-IR spectroscopy, and the consumed power was calculated from Lissajous’ figure analysis. In order to improve the decomposition performance, various TiO2-supported catalysts were employed.

With the rapid depletion of liquid oil, the urgency of finding a new alternative energy is raising. The most visible way could be the utilization some energy resources which currently never or rarely used before, such as methane or natural gas. As handling liquid matter is preferable and safe, it is necessary to convert gas reactants into liquid products. One candidate of the products is methanol which is already presence in our daily life. Currently, the industrial methanol synthesis is done via 2-stage process. This process can be easily transformed if the effective way, i.e. single-stage process, is discovered. One of the promising tools is plasma-based process1. Currently, catalytic plasma by dielectric barrier discharge has been performed in order to boost the production of methanol2,3. By the addition of Cu-Zn-Al (CZA), the methanol production showed the highest yield compared to other research works by plasma method4. Moreover, this research is a part of efforts encompassing the high production of methanol from direct methane by catalytic plasma process.

Non-catalytic conversion of methane (CH4) and nitrogen dioxide (NO2) into methanol (CH3OH) has been conducted and presented in this paper. Experiments were carried out using dielectric barrier discharge as the reaction medium in atmospheric pressure and temperature conditions. High yield production of methanol was achieved (18–20% mol) by single-stage plasma reaction with maximum selectivity of 32% mol. Compared to other oxidants, such as O2, the presence of NO2 in the plasma reaction resulted in higher methanol selectivity. For better understanding of the reactions, density functional theory calculations were also performed and discussed.

The synthesis of polycyclic aromatic hydrocarbons (PAHs) and the formation of soot platelets occur both during combustion at relatively low [O(2)], or under pyrolysis conditions. When the PAH size grows beyond the number of three-four condensed cycles, the partitioning of PAHs between the gas and particle phases favours the latter (i.e. adsorption). This study aims to assess which role the soot particle plays during PAH synthesis, in particular if catalytic or template effects of some sort can be exerted by the soot platelet on the adsorbed growing PAH-like radical. Our theoretical calculations indicate that chain elongation by ethyne addition cannot compete with cyclization when both can take place in the growing PAH-like radical, already in the gas phase. When it is adsorbed, cyclization is found to become easier than in the gas phase (more so, in terms of Gibbs free energy barriers, at higher temperatures), hinting at some sort of template effect, while chain elongation by ethyne addition becomes somewhat more difficult. The underlying soot platelet can assist (at lower temperatures) the formation of a larger aromatic hydrocarbon, by a final hydrogen abstraction from that endocyclic saturated carbon the newly formed cycle still bears. As an alternative (at higher temperature), a spontaneous hydrogen atom loss can take place. Finally, at rather low temperatures, the addition of the growing radical to the underlying soot platelet might occur and cause some reticulation, form more disordered structures, i.e. soot precursors instead of PAHs.

Decomposition of carbon dioxide (C02) by gliding arc plasma was examined. The plasma reactor was consisted of two triangles stainless steel plates which was connected to a 20 kV AC power supply. The gas entered through a nozzle tube from the upstream cylinder reactor and exit at the downstream of the reactor. The effect of total gas flow rates have been used to study the chemical process reaction in gliding plasma system. The model of active-chemical kinetic of C02 decomposition was built to explain the way of plasma reaction. Experiment results indicate the conversion of C02 reached 18% at the total gas flow rate of 1.5' 10.5m3s'1and produced CO and 02 as the main gaseous final products.