The role of contact time and input amount of 1,1,1,2-tetrafluoroethane (HFC-134a) on the catalyst lifetime and product selectivity in catalytic pyrolysis

2021 ◽  
Author(s):  
Ali Anus ◽  
Mahshab Sheraz ◽  
Sangjae Jeong ◽  
Caroline Mercy Andrew Swamidoss ◽  
Young-Min Kim ◽  
...  
Keyword(s):  
Contact Time ◽  
Catalytic Pyrolysis ◽  
Product Selectivity ◽  
Hfc 134A ◽  
Input Amount ◽  
Catalyst Lifetime

scholarly journals The Use of a γ-Al2O3 and MgO Mixture in the Catalytic Conversion of 1,1,1,2-Tetrafluoroethane (HFC-134a)

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 901
Author(s):  
Sangjae Jeong ◽  
Gamal Luckman Sudibya ◽  
Jong-Ki Jeon ◽  
Young-Min Kim ◽  
Caroline Mercy Andrew Swamidoss ◽  
...  
Keyword(s):  
High Temperature ◽  
Surface Area ◽  
Catalytic Pyrolysis ◽  
Acid Sites ◽  
Weak Acid ◽  
Complete Decomposition ◽  
Hfc 134A ◽  
Combined Use ◽  
Decomposition Efficiency ◽  
Catalyst Lifetime

This paper reports the improved efficiency of 1,1,1,2-tetrafluoroethane (HFC-134a) decomposition by combined use of MgO with γ-Al2O3. While a high temperature (>900 °C) was required to achieve 90% conversion during non-catalytic pyrolysis of HFC-134a, 100% conversion of HFC-134a was achieved at 600 °C by the use of γ-Al2O3. Among the three catalysts (γ-Al2O3, MgO, and CaO) tested in this study, γ-Al2O3 showed the highest HFC-134a decomposition efficiency, followed by MgO and CaO, due to its large surface area and large amount of weak acid sites. Also with the longest lifetime among the catalysts, durability in maintaining complete decomposition of HFC-134a was shown in γ-Al2O3. The addition of MgO to γ-Al2O3 was effective in extending the lifetime of γ-Al2O3 due to the efficient interaction between HF and MgO, which can delay the deactivation of γ-Al2O3. Compared to the double bed γ-Al2O3-MgO configuration, the use of a mixed γ-Al2O3-MgO bed extended the catalyst lifetime more effectively.

scholarly journals The key role of contact time in elucidating the mechanisms of enhanced decontamination by Fe0/MnO2/sand systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Viet Cao ◽  
Ghinwa Alyoussef ◽  
Nadège Gatcha-Bandjun ◽  
Willis Gwenzi ◽  
Chicgoua Noubactep
Keyword(s):  
Contact Time ◽  
Diffusive Transport ◽  
Iron Hydroxides ◽  
Iron Corrosion ◽  
Short Term ◽  
Batch Studies ◽  
Water Decontamination ◽  
Co Precipitation

AbstractMetallic iron (Fe0) has shown outstanding performances for water decontamination and its efficiency has been improved by the presence of sand (Fe0/sand) and manganese oxide (Fe0/MnOx). In this study, a ternary Fe0/MnOx/sand system is characterized for its discoloration efficiency of methylene blue (MB) in quiescent batch studies for 7, 18, 25 and 47 days. The objective was to understand the fundamental mechanisms of water treatment in Fe0/H2O systems using MB as an operational tracer of reactivity. The premise was that, in the short term, both MnO2 and sand delay MB discoloration by avoiding the availability of free iron corrosion products (FeCPs). Results clearly demonstrate no monotonous increase in MB discoloration with increasing contact time. As a rule, the extent of MB discoloration is influenced by the diffusive transport of MB from the solution to the aggregates at the bottom of the vessels (test-tubes). The presence of MnOx and sand enabled the long-term generation of iron hydroxides for MB discoloration by adsorption and co-precipitation. Results clearly reveal the complexity of the Fe0/MnOx/sand system, while establishing that both MnOx and sand improve the efficiency of Fe0/H2O systems in the long-term. This study establishes the mechanisms of the promotion of water decontamination by amending Fe0-based systems with reactive MnOx.

Effect of methane co-feeding on product selectivity of catalytic pyrolysis of biomass

2018 ◽  
Vol 303 ◽  
pp. 200-206 ◽  
Author(s):  
Hoda Shafaghat ◽  
Jungho Jae ◽  
Sang-Chul Jung ◽  
Jong-Ki Jeon ◽  
Chang Hyun Ko ◽  
...  
Keyword(s):  
Catalytic Pyrolysis ◽  
Product Selectivity ◽  
Pyrolysis Of Biomass

Leaching properties of slag generated by a gasification/vitrification unit: The role of pH, particle size, contact time and cooling method used

2012 ◽  
Vol 207-208 ◽  
pp. 44-50 ◽  
Author(s):  
K. Moustakas ◽  
Al. Mavropoulos ◽  
E. Katsou ◽  
K.-J. Haralambous ◽  
M. Loizidou
Keyword(s):  
Particle Size ◽  
Contact Time ◽  
Cooling Method

THM formation during chlorination of treated municipal wastewater

2002 ◽  
Vol 2 (3) ◽  
pp. 235-242 ◽  
Author(s):  
E. Koukouraki ◽  
E. Diamadopoulos
Keyword(s):  
Organic Carbon ◽  
Contact Time ◽  
Municipal Wastewater ◽  
Secondary Effluent ◽  
Batch Experiments ◽  
Limited Effect ◽  
Formation Potential ◽  
Coagulation Tests ◽  
Treated Municipal Wastewater

Chlorination batch experiments were conducted in order to estimate the concentration of THM and their formation potential in nitrified and partially nitrified secondary effluent. The role of contact time (up to 2 hours), chlorine dose (3 levels), pH and temperature on the formation of THM was evaluated. THM formation, as measured by individual concentration as well as formation potential, was high for the nitrified secondary effluent, while for the partially nitrified effluent the respective concentrations were low, due to the reaction of chlorine with ammonia to form chloramines. In general, THM concentrations progressively increased as contact time, pH and chlorine dose increased. Increase in temperature (from 15-25°C) showed a rather limited effect. In addition, coagulation tests were applied prior to chlorination of the nitrified effluent for removing organic carbon and thereby controlling the formation of THM. Alum was used as the coagulant in doses varying from 0.1 mM to 2.5 mM. As the coagulant dose increased, the removal of both DOC and absorbance at 254 nm increased, while THM formation decreased. The reduction in THM formation was more pronounced for coagulant doses higher than 1.5 mM.

The role of in situ generated morphological motifs and Cu(i) species in C2+ product selectivity during CO2 pulsed electroreduction

Nature Energy ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 317-325 ◽  
Author(s):  
Rosa M. Arán-Ais ◽  
Fabian Scholten ◽  
Sebastian Kunze ◽  
Rubén Rizo ◽  
Beatriz Roldan Cuenya
Keyword(s):  
Product Selectivity

scholarly journals CO2 Hydrogenation over Oxide-Supported PtCo Catalysts: The Role of the Oxide Support in Determining the Product Selectivity

2016 ◽  
Vol 128 (28) ◽  
pp. 8100-8105 ◽  
Author(s):  
Shyam Kattel ◽  
Weiting Yu ◽  
Xiaofang Yang ◽  
Binhang Yan ◽  
Yanqiang Huang ◽  
...  
Keyword(s):  
Co2 Hydrogenation ◽  
Product Selectivity ◽  
Oxide Support

Nickel and cobalt phosphides as effective catalysts for oxygen removal of dibenzofuran: role of contact time, hydrogen pressure and hydrogen/feed molar ratio

2015 ◽  
Vol 5 (6) ◽  
pp. 3403-3415 ◽  
Author(s):  
A. Infantes-Molina ◽  
E. Gralberg ◽  
J. A. Cecilia ◽  
Elisabetta Finocchio ◽  
E. Rodríguez-Castellón
Keyword(s):  
Catalytic Activity ◽  
Contact Time ◽  
Hydrogen Pressure ◽  
Oxygen Removal ◽  
Molar Ratio ◽  
Metal Loading ◽  
Molar Ratios ◽  
Feed Molar Ratio

The catalytic activity of nickel and cobalt phosphides, with a metal loading of 5 wt.%, supported on silica was investigated in the hydrodeoxygenation reaction (HDO) of dibenzofuran (DBF) as a model oxygenated compound at different contact times, H2 pressures and H2/DBF molar ratios.

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