scholarly journals Perfomance of Chromium-Exchanged Zeolite Catalysts in the Combustion of Volatile Organic Compound Pollutants

2004 ◽  
Vol 4 (2) ◽  
pp. 66
Author(s):  
Ahmad Zuhairi Abdullah ◽  
Mohamad Zallani Abu Bakar ◽  
Subhash Bhatia
Keyword(s):  
Resonance Effect ◽  
Coke Formation ◽  
Fixed Bed ◽  
Space Velocity ◽  
Zeolite Catalysts ◽  
Long Run ◽  
Acetate Methyl ◽  
Beta Zeolites ◽  
Volatile Organic ◽  
High Metal

The activity and stability of chromium-exchanged beta (Cr-BEA),mordenite (Cr-MOR), and ZSM-5 (Cr-ZSM-5) zeolites of different Si/Alratios for volatile organic compounds (VOCS) combustion were reported. A fixed-bed catalytic reactor operated between 100 and 500°C and at a gas hourly space velocity (GHSV) of 32,000 h'! was used for the study. Methanol, ethyl acetate, methyl ethyl ketone, benzene, hexane, toluene, and xylene, all at 2,000 ppm, were selected as the VOC model compounds. Oxygenated VOCs were more reactive while showing good carton dioxide yield. Aromatics were more stable due to their resonance effect but the reactivity increased with the attachment of an electron donor group such as the methyl group. Cr-ZSM- 5(240) demonstrated the highest hydrothermal stability due to its high Si/Al ratio. Despite giving a high initial activity due to its high metal loading, Cr-BEA(25) was susceptible to coking in the long run. The high coke formation in mordenite and beta zeolites was attributed to their high acidity, interconnecting channels of different sizes, and relatively larger pore sizes. The coke that formed on Cr-ZSM-5(240) was more carbonaceous and oxidized at higher temperatures.

scholarly journals Evaporated Palm Oil Cracking To Gasoline Over Zeolite Catalysts

2012 ◽  
Author(s):  
Tirena Bahnur Siregar ◽  
Nor Aishah Saidina Amin
Keyword(s):  
Reaction Temperature ◽  
Palm Oil ◽  
Fixed Bed ◽  
Nitrogen Adsorption ◽  
Space Velocity ◽  
Zeolite Catalysts ◽  
Fixed Bed Reactor ◽  
Gaseous Products ◽  
Weight Hourly Space Velocity ◽  
Oil Cracking

Peretakan bermangkin minyak kelapa sawit kepada gasolin menggunakan H–ZSM–5 dan H–Beta dijalankan pada tekanan atmosfera dan kadar alir mengikut berat 2.5 jam–1. Suhu tindak balas ditetapkan dalam julat 450°C to 525°C. Mangkin yang dikalsinkan telah dicirikan menggunakan teknik pembelauan sinar X, penjerapan piridina–spektrofotometri inframerah dan penjerapan nitrogen. Hasil cecair dan gas dianalisis menggunakan kromatografi gas (FID) dan (TCD). Peningkatan suhu tidak balas meninggikan penukaran minyak kelapa sawit. Penukaran minyak kelapa sawit dan kepemilihan gasolin tertinggi diperolehi dengan mangkin H–ZSM–5, masing–masing ialah 96.12% berat dan 29.92% berat. Walaupun penukaran minyak kelapa sawit dan kepemilihan gasolin untuk kedua–dua mangkin adalah tinggi, tetapi H–ZSM–5 menunjukkan hasil yang lebih baik berbanding H–Beta pada semua suhu. Gasolin yang dihasilkan menggunakan H–ZSM–5 mempunyai kandungan naftena yang tinggi, diikuti oleh isoparafin, olefin, aromatik dan sedikit paraffin, manakala gasolin yang terhadil menggunakan H–Beta mengandungi olefin, naftena, paraffin dan aromatik. Hasil sampingan utama adalah gas yang terdiri daripada komponen C1–C3 menggunakan H–ZSM–5 dan C3–C4 menggunakan H–Beta Kata kunci: Zeolit; H–ZSM–5; H–Beta; peretakan; minyak kelapa sawit; gasolin The catalytic cracking of palm oil to gasoline over H–ZSM–5 and H–Beta was studied in fixed bed reactor operated at atmospheric pressure and weight hourly space velocity (WHSV) of 2.5 h–1. The reaction temperature was varied between 450°C to 525°C. The calcined catalysts were characterized using X–Ray Diffraction (XRD), Pyridine Adsorption–Infrared Spectrophotometry (Py–IR) and Nitrogen Adsorption (NA) methods. The liquid and gaseous products were analyzed using (FID) and (TCD) gas chromatography respectively. Increase in reaction temperature led to higher palm oil conversion. The highest conversion and gasoline selectivity obtained at 525°C were 96.12 wt% and 29.92 wt% respectively with H–ZSM–5. Although the conversion and the gasoline selectivity of both catalysts was high, but H–ZSM–5 performed better than H–Beta at all temperature range. Gasoline produced using H–ZSM–5 consisted mainly of naphthenes beside isoparaffins, olefins, aromatics and a small amount of paraffins, while the gasoline obtained by using H–Beta contained olefins, naphthenes, paraffins and aromatics. Gas was the major side product, which consisted mainly of C1–C3 for using H–ZSM–5 and C3–C4 compounds for using H–Beta. Key words: Zeolite; H–ZSM–5; H–Beta; cracking, palm oil; gasoline

Dimethyldisulphide Hydrodesulphurization on NiCoMo / Al2O3 Catalyst

2017 ◽  
Vol 68 (7) ◽  
pp. 1496-1500
Author(s):  
Rami Doukeh ◽  
Mihaela Bombos ◽  
Ancuta Trifoi ◽  
Minodora Pasare ◽  
Ionut Banu ◽  
...  
Keyword(s):  
Good Accuracy ◽  
Fixed Bed ◽  
Continuous System ◽  
Space Velocity ◽  
Molar Ratio ◽  
Catalytic Reactor ◽  
Liquid Hourly Space Velocity ◽  
Hydrodesulfurization Process ◽  
Al2o3 Catalyst ◽  
Simplified Kinetic Model

Hydrodesulphurization of dimethyldisulphide was performed on Ni-Co-Mo /�-Al2O3 catalyst. The catalyst was characterized by determining the adsorption isotherms, the pore size distribution and the acid strength. Experiments were carried out on a laboratory echipament in continuous system using a fixed bed catalytic reactor at 50-100�C, pressure from 10 barr to 50 barr, the liquid hourly space velocity from 1h-1 to 4h-1 and the molar ratio H2 / dimethyldisulphide 60/1. A simplified kinetic model based on the Langmuir�Hinshelwood theory, for the dimethyldisulphide hydrodesulfurization process of dimethyldisulphide has been proposed. The results show the good accuracy of the model.

scholarly journals Oxidation of Volatile Organic Compounds by Highly Efficient Metal Zeolite Catalysts

ChemCatChem ◽  
2018 ◽  
Vol 10 (17) ◽  
pp. 3754-3760 ◽  
Author(s):  
Olívia S. G. P. Soares ◽  
António M. Fonseca ◽  
Pier Parpot ◽  
José J. M. Órfão ◽  
Manuel F. R. Pereira ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Zeolite Catalysts ◽  
Highly Efficient ◽  
Volatile Organic

Dynamic Modeling of CATOFIN® Fixed-Bed Iso-Butane Dehydrogenation Reactor for Operational Optimization

2016 ◽  
Vol 14 (1) ◽  
pp. 491-515 ◽  
Author(s):  
Zeeshan Nawaz
Keyword(s):  
Coke Formation ◽  
Fixed Bed ◽  
Process Intensification ◽  
Operating Conditions ◽  
Catalytic Dehydrogenation ◽  
Heating Rates ◽  
Reactor Model ◽  
Fuel Gas ◽  
Bed Temperature ◽  
Operational Optimization

AbstractThe catalytic dehydrogenation of iso-butane to iso-butylene is an equilibrium limited endothermic reaction and requires high temperature. The catalyst deactivates quickly, due to deposition of carbonaceous species and countered by periodic regeneration. The reaction-engineering constraints are tied up with operation and/or technology design features. CATOFIN® is a sophisticated commercialized technology for propane/iso-butane dehydrogenation using multiple adiabatic fixed-bed reactors having Cr2O3/Al2O3 as catalyst, that undergo cyclic operations (~18–30m); dehydrogenation, regeneration, evacuation, purging and reduction. It is always a concern, how to maintain CATOFIN® reactor at an optimum production, while overcoming gradual decrease of heat in catalyst bed and deactivation. A homogeneous one-dimensional dynamic reactor model for a commercial CATOFIN® fixed-bed iso-butane dehydrogenation reactor is developed in an equation oriented (EO) platform Aspen Custom Modeler (ACM), for operational optimization and process intensification. Both reaction and regeneration steps were modeled and results were validated. The model predicts the dynamic behavior and demonstrates the extent of catalyst utilization with operating conditions and time, coke formation and removal, etc. The model computes optimum catalyst bed temperature profiles, feed rate, pre-heating, rates for reaction and regeneration, fuel gas requirement, optimum catalyst amount, overall cycle time optimization, and suggest best operational philosophy.

Effects of Cu and K Promoters on the Catalytic Performance of Iron-Based Nanocatalyst for Fischer-Tropsch Synthesis

2013 ◽  
Vol 832 ◽  
pp. 15-20 ◽  
Author(s):  
Sara Faiz Hanna Tasfy ◽  
Noor Asmawati Mohd Zabidi ◽  
Duvvuri Subbarao
Keyword(s):  
Atmospheric Pressure ◽  
Fixed Bed ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Reactant Ratio ◽  
Impregnation Method ◽  
Fischer Tropsch ◽  
Heavy Hydrocarbons ◽  
Co Conversion ◽  
Iron Based

Iron-based nanocatalyst was prepared via impregnation method on SiO2 support. The effects of promoters, namely, K and Cu, on the physical properties and catalytic performance in FTS have been investigated. The FTS performance of the synthesized nanocatalysts was examined in a fixed-bed microreactor at temperature of 523K, atmospheric pressure, 1.5 reactant ratio (H2/CO) and space velocity of 3L/g-cat.h. In FTS reaction, Cu promoter resulted in a lower CO conversion and C5+ hydrocarbons selectivity but higher selectivity to the lighter hydrocarbons (C1-C4) comparedto those obtained using the K promoter. Higher CO conversion (28.9%) and C5+ hydrocarbons selectivity (54.4%) were obtained using K as a promoter compared to that of Cu promoter. However, the K-promoted nanocatalyst resulted in a lower CO conversion but higher selectivity of the heavy hydrocarbons (C5+) compared to those obtained using the un-promoted nanocatalyst.

scholarly journals Volatile Organic Compounds (VOCs) of Endophytic Fungi Growing on Extracts of the Host, Horseradish (Armoracia rusticana)

Metabolites ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 451 ◽  
Author(s):  
Tamás Plaszkó ◽  
Zsolt Szűcs ◽  
Zoltán Kállai ◽  
Hajnalka Csoma ◽  
Gábor Vasas ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Soil Fungi ◽  
Dimethyl Sulfide ◽  
Gas Chromatography Mass Spectrometry ◽  
Malt Extract ◽  
Armoracia Rusticana ◽  
Acetate Methyl ◽  
Agar Film ◽  
Volatile Organic

The interaction between plant defensive metabolites and different plant-associated fungal species is of high interest to many disciplines. Volatile organic compounds (VOCs) are natural products that are easily evaporated under ambient conditions. They play a very important role in inter-species communication of microbes and their hosts. In this study, the VOCs produced by 43 different fungal isolates of endophytic and soil fungi during growth on horseradish root (Armoracia rusticana) extract or malt extract agar were examined, by using headspace-gas chromatography-mass spectrometry (headspace-GC-MS) and a high relative surface agar film as a medium. The proposed technique enabled sensitive detection of several typical VOCs (acetone, methyl acetate, methyl formate, ethyl acetate, methyl butanol isomers, styrene, beta-phellandrene), along with glucosinolate decomposition products, including allyl cyanide and allyl isothiocyanate and other sulfur-containing compounds—carbon disulfide, dimethyl sulfide. The VOC patterns of fungi belonging to Setophoma, Paraphoma, Plectosphaerella, Pyrenochaeta, Volutella, Cadophora, Notophoma, and Curvularia genera were described for the first time. The VOC pattern was significantly different among the isolates. The pattern was indicative of putative myrosinase activity for many tested isolates. On the other hand, endophytes and soil fungi as groups could not be separated by VOC pattern or intensity.

Comparative Study on the Kinetic Modeling of the Oxidative Coupling of Methane in Laboratory and Bench Scales

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Nakisa Yaghobi ◽  
Mir Hamid Reza Ghoreishy
Keyword(s):  
Kinetic Models ◽  
Oxidative Coupling ◽  
Consumption Rate ◽  
Linear Regression Analysis ◽  
Fixed Bed ◽  
Space Velocity ◽  
Oxidative Coupling Of Methane ◽  
Power Law Model ◽  
Fixed Bed Reactors ◽  
Rate Of Reaction

The aim of this work is to develop and compare kinetic models for the oxidative coupling of methane (OCM) based on the gas hourly space velocity (GHSV) value and CH4/O2 ratio in two scales: laboratory and bench. The experiments were carried out in tubular fixed bed reactors at 1023 K, using 0.7-1.5 g and 30 g of perovskite titanate as the reaction catalyst for laboratory and bench scales, respectively. The various GHSVs (8000, 12000, 17000 h-1) and (3400, 4300, 5200 h-1) and methane to oxygen ratios (1, 2, 3, 4, 7.5) and (2, 2.5, 3) were selected for laboratory and bench scales, respectively. We have proposed a mechanism in which the consumption rate of methane is always twice of production rate of C2. A power law model was assumed for rate of reaction in terms of partial pressure of oxygen and methane. Using a linear regression analysis, the kinetic models were determined. Comparison of the calculated rate of reaction with the experimentally measured data confirmed the accuracy and applicability of the developed model for both scales.

Influence Factors of Denitration Study on Catalyst Mn-Ce/TiO2

2013 ◽  
Vol 634-638 ◽  
pp. 526-530
Author(s):  
Chun Xiang Geng ◽  
Qian Qian Chai ◽  
Wei Yao ◽  
Chen Long Wang
Keyword(s):  
Reaction Temperature ◽  
Catalytic Reduction ◽  
Removal Rate ◽  
Load Capacity ◽  
Fixed Bed ◽  
Influence Factors ◽  
Space Velocity ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Ammonia Gas

Selective Catalytic Reduction (SCR) processes have been one of the most widely used denitration methods at present and the property of low tempreture catalyst becomes a hot research. The Mn-Ce/TiO2 catalyst was prepared by incipient impregnation method. The influence of load capacity, reaction temperature, O2 content, etc. on denitration were studied by a fixed bed catalyst reactor with ammonia gas. Results showed that catalyst with load capacity 18% performed high NO removal rate of 90% at conditions of reaction temperature 160°C, low space velocity, NH3/NO molar ratio 1: 1, O2 concentration 6%.

Comparison and assessment of zeolite catalysts performance dimethyl ether and light olefins production through methanol: a review

2019 ◽  
Vol 39 (3) ◽  
pp. 157-177 ◽  
Author(s):  
Ehsan Kianfar
Keyword(s):  
Dimethyl Ether ◽  
Raw Materials ◽  
Fixed Bed ◽  
Value Added ◽  
Zeolite Catalysts ◽  
Present Review ◽  
Light Olefins ◽  
Light Olefin ◽  
Production Methods ◽  
Olefin Production

AbstractThe present review focuses on a comparison and assessment of zeolite catalyst performance of dimethyl ether and light olefin production through methanol. Dimethyl ether is a clean fuel which needs diverse processes to be produced. Methanol to dimethyl ether is a very novel process which offers considerable advantages versus additional processes for the production of dimethyl ether. The corresponding fixed-bed reactors compose the most important section of such a process. Production of dimethyl ether by the mentioned process is of high importance since it can be catalytically transferred to a substance with the value of propylene. Furthermore, in case of capability to transfer low-purity methanol into dimethyl ether, less expensive methanol can be consequently achieved with higher value added. In the petrochemical industry, light olefins, for example, ethylene and propylene, can be used as raw materials for the production of polyolefin. The present review aims to produce dimethyl ether in order to reach olefin substances, initially conducting a compressive assessment on production methods of olefin substances.

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