Highly radiating hydrogen flames: Effect of toluene concentration and phase

2020 ◽  
Author(s):  
Michael J. Evans ◽  
Douglas B. Proud ◽  
Paul R. Medwell ◽  
Heinz Pitsch ◽  
Bassam B. Dally
Keyword(s):  
Toluene Concentration

The comparison of trichloroethylene removal rates by methane- and aromatic-utilizing microorganisms

1998 ◽  
Vol 38 (7) ◽  
pp. 19-24 ◽  
Author(s):  
C.-J. Lu ◽  
C. M. Lee ◽  
M.-S. Chung
Keyword(s):  
Cell Concentration ◽  
Removal Rate ◽  
Carbon Sources ◽  
Batch Reactors ◽  
Initial Cell Concentration ◽  
Removal Rates ◽  
Initial Cell ◽  
Toluene Concentration ◽  
Cell Source ◽  
Removal Efficiencies

The comparison of TCE cometabolic removal by methane, toluene, and phenol utilizers was conducted with a series of batch reactors. Methane, toluene, or phenol enriched microorganisms were used as cell source. The initial cell concentration was about 107 cfu/mL. Methane, toluene, and phenol could be readily biodegraded resulting in the cometabolic removal of TCE. Among the three primary carbon sources studied, the presence of phenol provided the best cometabolic removal of TCE. When the concentration of carbon source was 3 mg-C/L, the initial TCE removal rates initiated by methane, toluene, and phenol utilizers were 1.5, 30, and 100 μg/L-hr, respectively. During the incubation period of 80 hours, TCE removal efficiencies were 26% and 96% with the presence of methane and toluene, respectively. However, it was 100% within 20 hours with the presence of phenol. For phenol utilizers, the initial TCE removal rates were about the same, when the phenol concentrations were 1.35, 2.7, and 4.5 mg/L. However, TCE removal was not proportional to the concentrations of phenol. TCE removal was hindered when the phenol concentration was higher than 4.5 mg/L because of the rapid depletion of dissolved oxygen. The presence of toluene also initiated cometabolic removal of TCE. The presence of toluene at 3 and 5 mg/L resulted in similar TCE removal. The initial TCE removal rate was about 95 μg/L-hr at toluene concentrations of 3 and 5 mg/L compared to 20 μg/L-hr at toluene concentration of 1 mg/L.

scholarly journals Electrokinetic-enhanced removal of toluene from physically heterogeneous granular porous media

2020 ◽  
pp. qjegh2020-073
Author(s):  
Richard Thomas Gill ◽  
Steven Thornton ◽  
Michael J. Harbottle ◽  
Jonathan W. N. Smith
Keyword(s):  
Porous Media ◽  
Transport Processes ◽  
Effective Mechanism ◽  
Content Type ◽  
Bench Scale ◽  
Toluene Concentration ◽  
Granular Porous Media ◽  
Supplementary Material ◽  
Scale Experiment ◽  
Water Saturated

Electrokinetics (EK) was applied to enhance biodegradation of toluene in the low hydraulic conductivity (K) zone of a physically heterogeneous water-saturated granular porous media. The hypothesis tested was that EK transport processes, which operate independently of advection, can deliver a limiting amendment, nitrate, across a high-K–low-K boundary to stimulate bioremediation. Two types of experiment were evaluated: (1) bench-scale tests that represented the active EK system and physically heterogeneous sediment configuration; (2) microcosms that represented biodegradation in the bench-scale tests under ideal conditions. The bench-scale experiment results showed a rapid decrease in toluene concentration during the application of EK that was attributed to electroosmotic removal from low-K zones. Comparison of toluene removal rates by electroosmosis and biodegradation (microcosm) confirmed that electroosmosis was the most effective mechanism under the conditions evaluated. Overall, this work challenges the original hypothesis and indicates that, at the field scale, the most favourable conditions for biodegradation are likely to be achieved by applying EK to increase contaminant flux across the low-K–high-K boundary (out of the low-K zone) and allowing biodegradation to occur in the high-K zone either by natural attenuation or enhanced by amendment addition.Supplementary material: Supplementary material is available at https://doi.org/10.6084/m9.figshare.c.5174554

scholarly journals Coupled Plasma-Catalytic System with Rang 19pr Catalyst for Conversion of Tar

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Michał Młotek ◽  
Joanna Woroszył ◽  
Bogdan Ulejczyk ◽  
Krzysztof Krawczyk
Keyword(s):  
Catalytic System ◽  
Gas Flow ◽  
Model Compound ◽  
Calorific Value ◽  
Homogeneous System ◽  
Toluene Concentration ◽  
Gliding Discharge ◽  
Outlet Stream ◽  
The One ◽  
Pyrolysis Of Biomass

Abstract A coupled plasma-catalytic system (CPCS) for the conversion of toluene was investigated and compared to the homogeneous system of gliding discharge plasma. Toluene was used as a model compound, which is present in tars. The study was carried out at atmospheric pressure, in a gas composition similar to the one obtained during pyrolysis of biomass. The effect of the initial toluene concentration, energy supplied to gliding discharge (GD) and the presence of a catalyst on the conversion of toluene was studied. Both the composition of outlet gas and its calorific value were monitored. Based on the obtained results it can be concluded that the conversion of toluene increases with the increase of gliding discharge power. The highest toluene conversion (89%) was received in the coupled plasma-catalytic system (catalyst: RANG-19PR) under the following conditions: CO (0.13 mol. fr.), CO2 (0.12 mol. fr.), H2 (0.25 mol. fr.), N2 (0.50 mol. fr.) and 4400 ppm of toluene with a gas flow rate of 1000 Nl/h. The composition of the outlet gas in the homogeneous system and in the CPCS changed in the range of a few percents. Toluene levels were reduced tenfold. Benzene, C3 and C4 hydrocarbons, as well as acetylene, ethylene and ethane, were detected in the outlet stream in trace amounts. Carbon deposits were present in the reactor. The products of methanation of carbon oxides were detected in the both studied systems. A mechanism of toluene decomposition in the CPCS was proposed. The application of the catalyst brought about an increase in the calorific value of the outlet gas. It was above the minimal level demanded by engines and turbines.

Photoacoustic spectroscopy-based detector for measuring benzene and toluene concentration in gas and liquid samples

2011 ◽  
Vol 22 (12) ◽  
pp. 125602 ◽  
Author(s):  
Veronika Hanyecz ◽  
Árpád Mohácsi ◽  
Sándor Puskás ◽  
Árpád Vágó ◽  
Gábor Szabó
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Toluene Concentration ◽  
Liquid Samples

scholarly journals Application of electronic nose to effectiveness monitoring of air contaminated with toluene vapors biofiltration process

2018 ◽  
Vol 57 ◽  
pp. 02014
Author(s):  
Bartosz Szulczyński ◽  
Piotr Rybarczyk ◽  
Jacek Gębicki
Keyword(s):  
Gas Chromatography ◽  
Removal Efficiency ◽  
Electronic Nose ◽  
Environmental Isolates ◽  
Effectiveness Monitoring ◽  
Toluene Concentration ◽  
On Line ◽  
Reliable Quantification ◽  
Odorous Compound ◽  
Mlr Model

The research presents the application of electronic nose (combined with MLR model) to on-line effectiveness monitoring of biofiltration of air contaminated with hydrophobic, odorous compound (toluene vapors). The research was conducted using two-section biotrickling filter inhabited by Candida environmental isolates. Gas chromatography was used as the comparative technique to obtain reliable quantification of toluene concentration in the samples. After about 200 hours of the process, a removal efficiency of 49% was obtained.

Effect of Toluene Addition on Hydrogen Sulfide Combustion Under Claus Condition

2013 ◽  
Author(s):  
Salisu Ibrahim ◽  
Ahmed S. AlShoaibi ◽  
Ashwani K. Gupta
Keyword(s):  
Hydrogen Sulfide ◽  
Flame Temperature ◽  
Reactor Performance ◽  
Heating Value ◽  
Toluene Concentration ◽  
Maximum Value ◽  
Baseline Case ◽  
Claus Reactor ◽  
Large Heating ◽  
Sulfur Capture

Experimental results on the effect of different amounts of toluene addition to H2S gas stream are presented. Three toluene concentrations of 0.5%, 1% and 5% in H2S are presented and compared with the baseline case of 100% H2S/air combustion. Temperature data showed that addition of toluene to H2S gas stream increases the flame temperature because of large heating value associated with toluene. Addition of toluene resulted in the production of H2, which increased with increase in the amounts of toluene addition. Furthermore, increased addition of toluene concentration increased the asymptotic value of hydrogen sulfide due to oxidation competition between the formed H2 and H2S. The results also showed that the presence of CO triggers the formation of COS with toluene addition due to reaction of CO with SO2. The results revealed that SO2 mole fraction increased to a maximum value then decayed with distance along the reactor. Addition of toluene increased the rate of SO2 decay. These results have direct impact on sulfur capture in Claus reactor performance for sulfur capture.

Toluene Degradation by Thermal Catalytic Oxidation over K-OMS-2 Catalysts

2014 ◽  
Vol 931-932 ◽  
pp. 22-26
Author(s):  
Patiparn Boonruam ◽  
Sutasinee Neramittagapong ◽  
Arthit Neramittagapong ◽  
Kitirote Wantala
Keyword(s):  
Manganese Oxide ◽  
Hydrothermal Method ◽  
Space Velocity ◽  
Precipitation Method ◽  
Effect Of Temperature ◽  
Toluene Degradation ◽  
Toluene Removal ◽  
Surface Areas ◽  
Toluene Concentration ◽  
Xrd Patterns

The goal of this research was to synthesize two different catalysts, namely K-OMS-2 and MnOx. The K-OMS-2 was an octahedral manganese complex prepared by hydrothermal method, while manganese oxide (MnOx) was directly synthesized by precipitation method. Both catalysts were employed to decompose toluene, an organic solvent that is widely used in industries. The catalysts were characterized by means of X-ray diffraction (XRD) and N2-physorption. The surface areas of K-OMS-2 and MnOx were 83.50 and 20.04 m2/g, respectively. The precipitation route gave XRD patterns of γ-Mn2O3 structure, and a successful structure of an octahedral molecular sieve manganese oxide was obtained by the hydrothermal method. The toluene degradation was carried out in gas hourly space velocity (GHSV) range of 20,000-60,000 h-1 with toluene concentration of 7,700 ppmv. The higher GHSV over K-OMS-2 gave the lower contact time consequently resulting in the lower %toluene degradation, whereas the best GHSV over γ-Mn2O3 was suitable at 40,000 h-1. The complete oxidation temperature of toluene over K-OMS-2 occurred at 260 °C and was lower than the temperature by γ-Mn2O3 at 300 °C. The higher surface area of K-OMS-2 may not facilitate internal toluene diffusion to active K-OMS-2 sites because molecular toluene (5.6 Å) cannot migrate through its smaller pore diameter (4.6 Å); however, the fully oxidized K-OMS-2 can provide higher average oxidation state (AOS) and higher amount of lattice oxygen assisting toluene degradation compared to γ-Mn2O3. The full factorial design of experiment (DOE) exhibited a strong effect of temperature and catalyst types on toluene removal; in contrast gas hour space velocity (GHSV) exhibited no significant effect on %toluene removal even with increasing GHSV.

scholarly journals Volatile Organic Compound (VOC) Removal via Photocatalytic Oxidation Using TiO2 Coated Nanofilms

2017 ◽  
Vol 15 (7) ◽  
pp. 491-501
Author(s):  
Sunun KHAMI ◽  
Wipawee KHAMWICHIT ◽  
Ratthapol RANGKUPAN ◽  
Kowit SUWANNAHONG
Keyword(s):  
Bacterial Cellulose ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Average Particle Size ◽  
Average Particle ◽  
Experimental Conditions ◽  
Electrospinning Technique ◽  
Photocatalytic Reactor ◽  
Toluene Concentration ◽  
Spinning Process

In this paper, toluene removal via photocatalytic oxidation using TiO2 dip coated nanofilms is presented. Nanofilms were synthesized from bacterial cellulose using the electrospinning technique. The physical properties of the nanofilms were analyzed by scanning electron microscopy (SEM). The ratio of bacterial cellulose/nylon used in the spinning process was 0.165:1. The results from SEM showed that the structure of the TiO2 composite nanofilms was rutile crystalline with an average particle size of 20 nm, and synthesized nanofilms had an average size of 20 - 30 nm. The band gap energies of TiO2-dip coated nanofilms ranged from 3.18 - 3.21 eV. SEM results of TiO2 coated nanofilms suggested that the TiO2 was rather uniformly distributed onto the surface of the nanofilms. The actual amount of TiO2 coated on the nanofilms was estimated using thermogravimetric analysis (TGA) for 1x1 cm2 surface area. It was found that 0.1852, 0.2897 and 0.7275 mg of TiO2 were coated on the surface of the nanofilms for 1, 2.5 and 5 % (weight) TiO2 dosage, respectively. The photocatalytic activity of the nanofilms was tested for the removal of gaseous toluene in a photocatalytic reactor. Experimental conditions were set as follows: UV light intensity of approximately 2.7 mW.cm-2, flow rate of 0.2 L.min-1, and an initial toluene concentration of about 200±20 ppm, and a retention time at 200 min. The degradation rate of toluene increased with increasing dosage of TiO2 from 1, 2.5 and 5 %. The nanofilms at a 5 % dosage yielded the highest removal efficiency of 92.71 %, followed by the 2.5 and 1 % dosage, respectively.

scholarly journals TOLUENE DEGRADATION BY FREE STAPHYLOCOCCUS GALLINARUM AND IMMOBILIZED ON MULTI-WALLED CARBON NANOTUBES

2021 ◽  
Vol 10 (1) ◽  
pp. 61-73
Author(s):  
Fatemeh Heydarnezhad ◽  
Mehran Hoodaji ◽  
Mahdi Shahriarinour ◽  
Arezoo Tahmourespour
Keyword(s):  
Carbon Nanotubes ◽  
Immobilized Cells ◽  
Toluene Degradation ◽  
Toluene Concentration ◽  
Degrading Bacterium ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Optimized Conditions ◽  
Central Composite ◽  
Staphylococcus Gallinarum

Hydrocarbons pollution is a most important environmental and healthanxiety . Using free and immobilized bacteria could be a suitable attitude to find a proper bioaugmentation agent. A toluene degrading bacterium was isolated from oil-contaminated environs (located in Bandar-Anzali, Guilan, Iran). The strain was molecularly identified as Staphylococcus gallinarum ATHH41 (Accession number: KX344723) by partial sequencing of 16SrDNA gene. The response surface methodology (RSM) was expended for biodegradation of the toluene by ATHH41. The central composite design (CCD) was utilized to optimize pH, temperature, and toluene concentration by ATHH41. In accordance with the optimization purpose of the Design-Expert software, the optimum circumstances of toluene degradation were obtained when pH, temperature and toluene concentration were adjusted to 7.68, 31.73°C and 630.04 mg.l-1, respectively. Multi-walled carbon nanotubes (MWCNTs) were used to immobilize the strain. Infrared spectroscopy and scanning electron microscopy showed that the cells adhered to the MWCNT surface and developed a biofilm. Results reveal that free cells were able to degrade 68.01% of the toluene as the sole carbon and energy source within 24 h under optimized conditions. The immobilized cells reached 95.68%.

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