scholarly journals Catalytic Hot Gas Cleanup of Biomass Gasification Producer Gas via Steam Reforming Using Nickel-Supported Clay Minerals

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1875
Author(s):  
Prashanth Reddy Buchireddy ◽  
Devin Peck ◽  
Mark Zappi ◽  
Ray Mark Bricka
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Steam Reforming ◽  
Catalyst Deactivation ◽  
Nickel Content ◽  
Coke Formation ◽  
Biomass Gasification ◽  
Supported Nickel Catalyst ◽  
Fuel Gas ◽  
Removal Efficiencies

Amongst the issues associated with the commercialization of biomass gasification, the presence of tars has been one of the most difficult aspects to address. Tars are an impurity generated from the gasifier and upon their condensation cause problems in downstream equipment including plugging, blockages, corrosion, and major catalyst deactivation. These problems lead to losses of efficiency as well as potential maintenance issues resulting from damaged processing units. Therefore, the removal of tars is necessary in order for the effective operation of a biomass gasification facility for the production of high-value fuel gas. The catalytic activity of montmorillonite and montmorillonite-supported nickel as tar removal catalysts will be investigated in this study. Ni-montmorillonite catalyst was prepared, characterized, and tested in a laboratory-scale reactor for its efficiency in reforming tars using naphthalene as a tar model compound. Efficacy of montmorillonite-supported nickel catalyst was tested as a function of nickel content, reaction temperature, steam-to-carbon ratio, and naphthalene loading. The results demonstrate that montmorillonite is catalytically active in removing naphthalene. Ni-montmorillonite had high activity towards naphthalene removal via steam reforming, with removal efficiencies greater than 99%. The activation energy was calculated for Ni-montmorillonite assuming first-order kinetics and was found to be 84.5 kJ/mole in accordance with the literature. Long-term activity tests were also conducted and showed that the catalyst was active with naphthalene removal efficiencies greater than 95% maintained over a 97-h test period. A little loss of activity was observed with a removal decrease from 97% to 95%. To investigate the decrease in catalytic activity, characterization of fresh and used catalyst samples was performed using thermogravimetric analysis, transmission electron microscopy, X-ray diffraction, and surface area analysis. The loss in activity was attributed to a decrease in catalyst surface area caused by nickel sintering and coke formation.

scholarly journals Ni-based catalysts for steam reforming of tar model derived from biomass gasification

2019 ◽  
Vol 90 ◽  
pp. 01015 ◽  
Author(s):  
Ru Shien Tan ◽  
Afizah Alir ◽  
Saiful Azam Mohamad ◽  
Khairuddin Md Isa ◽  
Tuan Amran Tuan Abdullah
Keyword(s):  
Catalytic Activity ◽  
Steam Reforming ◽  
Coke Formation ◽  
Fixed Bed ◽  
Biomass Gasification ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Variable Pressure ◽  
Major Barrier ◽  
Filamentous Carbon

Tar formation during biomass gasification is a major barrier to utilise the produced syngas, which clogs processing equipment. In the present study, steam reforming of gasification-derived tar (phenol, toluene, naphthalene, and pyrene) was catalysed by Ni/dolomite, Ni/dolomite/Al2O3, Ni/dolomite/La2O3, Ni/dolomite/CeO2, and Ni/dolomite/ZrO2 for hydrogen production. The steam reforming experiment was conducted in a fixed bed reactor at 700 °C and the steam-to-carbon molar ratio of 1 under atmospheric pressure. After the catalytic test, the spent catalysts were characterised by thermogravimetric analysis and variable-pressure scanning electron microscope. The aim of this study is to investigate the catalytic activity of Ni-based catalysts in terms of tar conversion and their deactivation characteristic. The current results revealed that all the catalysts showed almost full conversion of tar (98.8%-99.9%) and considerably low amount of coke deposited in the form of amorphous and filamentous carbon (15.9-178.5 mg gcat-1). Among the catalysts studied, Ni/dolomite/La2O3 gave the highest catalytic activity for steam reforming of gasified biomass tar and lowest coke formation.

scholarly journals Study of deactivation in mesocellular foam carbon (MCF-C) catalyst used in gas-phase dehydrogenation of ethanol

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoottapong Klinthongchai ◽  
Seeroong Prichanont ◽  
Piyasan Praserthdam ◽  
Bunjerd Jongsomjit
Keyword(s):  
Catalytic Activity ◽  
Pore Size ◽  
Gas Phase ◽  
Surface Area ◽  
Active Sites ◽  
Operating Temperature ◽  
Coke Formation ◽  
Ethanol Conversion ◽  
Deactivation Of Catalyst ◽  
Dehydrogenation Of Ethanol

AbstractMesocellular foam carbon (MCF-C) is one the captivating materials for using in gas phase dehydrogenation of ethanol. Extraordinary, enlarge pore size, high surface area, high acidity, and spherical shape with interconnected pore for high diffusion. In contrary, the occurrence of the coke is a majority causes for inhibiting the active sites on catalyst surface. Thus, this study aims to investigate the occurrence of the coke to optimize the higher catalytic activity, and also to avoid the coke formation. The MCF-C was synthesized and investigated using various techniques. MCF-C was spent in gas-phase dehydrogenation of ethanol under mild conditions. The deactivation of catalyst was investigated toward different conditions. Effects of reaction condition including different reaction temperatures of 300, 350, and 400 °C on the deactivation behaviors were determined. The results indicated that the operating temperature at 400 °C significantly retained the lowest change of ethanol conversion, which favored in the higher temperature. After running reaction, the physical properties as pore size, surface area, and pore volume of spent catalysts were decreased owing to the coke formation, which possibly blocked the pore that directly affected to the difficult diffusion of reactant and caused to be lower in catalytic activity. Furthermore, a slight decrease in either acidity or basicity was observed owing to consumption of reactant at surface of catalyst or chemical change on surface caused by coke formation. Therefore, it can remarkably choose the suitable operating temperature to avoid deactivation of catalyst, and then optimize the ethanol conversion or yield of acetaldehyde.

scholarly journals Pt-Sn Supported on Beta Zeolite with Enhanced Activity and Stability for Propane Dehydrogenation

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Su-Un Lee ◽  
You-Jin Lee ◽  
Soo-Jin Kwon ◽  
Jeong-Rang Kim ◽  
Soon-Yong Jeong
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
High Surface ◽  
Coke Formation ◽  
Propane Dehydrogenation ◽  
Coke Deposition ◽  
Beta Zeolite ◽  
Lower Amount ◽  
Metal Catalyst ◽  
Beta Zeolites

With the growing global propylene demand, propane dehydrogenation (PDH) has attracted great attention for on-purpose propylene production. However, its industrial application is limited because catalysts suffer from rapid deactivation due to coke deposition and metal catalyst sintering. To enhance metal catalyst dispersion and coke resistance, Pt-based catalysts have been widely investigated with various porous supports. In particular, zeolite can benefit from large surface area and acid sites, which favors high metal dispersion and promoting catalytic activity. In this work, we investigated the PDH catalytic properties of Beta zeolites as a support for Pt-Sn based catalysts. In comparison with Pt-Sn supported over θ-Al2O3 and amorphous silica (Q6), Beta zeolite-supported Pt-Sn catalysts exhibited a different reaction trend, achieving the best propylene selectivity after a proper period of reaction time. The different PDH catalytic behavior over Beta zeolite-supported Pt-Sn catalysts has been attributed to their physicochemical properties and reaction mechanism. Although Pt-Sn catalyst supported over Beta zeolite with low acidity showed low Pt dispersion, it formed a relatively lower amount of coke on PDH reaction and maintained a high surface area and active Pt surfaces, resulting in enhanced stability for PDH reaction. This work can provide a better understanding of zeolite-supported Pt-Sn catalysts to improve PDH catalytic activity with high selectivity and low coke formation.

scholarly journals Syngas Production via CO2 Reforming of Methane Over SrNiO3 and CeNiO3 Perovskites

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2928
Author(s):  
Naushad Ahmad ◽  
Fahad Alharthi ◽  
Manawwer Alam ◽  
Rizwan Wahab ◽  
Salim Manoharadas ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Active Sites ◽  
Catalyst Deactivation ◽  
Dry Reforming Of Methane ◽  
Volume Number ◽  
Syngas Production

The development of a transition-metal-based catalyst with concomitant high activity and stability due to its distinguishing characteristics, yielding an abundance of active sites, is considered to be the bottleneck for the dry reforming of methane (DRM). This work presents the catalytic activity and durability of SrNiO3 and CeNiO3 perovskites for syngas production via DRM. CeNiO3 exhibits a higher specific surface area, pore volume, number of reducible species, and nickel dispersion when compared to SrNiO3. The catalytic activity results demonstrate higher CH4 (54.3%) and CO2 (64.8%) conversions for CeNiO3, compared to 22% (CH4 conversion) and 34.7% (CO2 conversion) for SrNiO3. The decrease in catalytic activity after replacing cerium with strontium is attributed to a decrease in specific surface area and pore volume, and nickel active sites covered with strontium carbonate. The stability results reveal the deactivation of both the catalysts (SrNiO3 and CeNiO3) but SrNiO3 showed more deactivation than CeNiO3, as demonstrated by deactivation factors. The catalyst deactivation is mainly attributed to carbon deposition and these findings are verified by characterizing the spent catalysts.

Study of Deactivation in Mesocellular Foam Carbon (MCF-C) Catalyst Used in Gas-Phase Dehydrogenation of Ethanol

2021 ◽  
Author(s):  
Yoottapong Klinthongchai ◽  
Seeroong Prichanont ◽  
Piyasan Praserthdam ◽  
Bunjerd Jongsomjit
Keyword(s):  
Catalytic Activity ◽  
Pore Size ◽  
Gas Phase ◽  
Surface Area ◽  
Active Sites ◽  
Operating Temperature ◽  
Coke Formation ◽  
Ethanol Conversion ◽  
Deactivation Of Catalyst ◽  
Dehydrogenation Of Ethanol

Abstract Mesocellular foam carbon (MCF-C) is one the captivating materials for using in gas phase dehydrogenation of ethanol. Extraordinary, enlarge pore size, high surface area, high acidity, and spherical shape with interconnected pore for high diffusion. In contrary, the occurrence of the coke is a majority causes for inhibiting the active sites on catalyst surface. Thus, this study aims to investigate the occurrence of the coke to optimize the higher catalytic activity, and also to avoid the coke formation. The MCF-C was synthesized and investigated using various techniques. MCF-C was spent in gas-phase dehydrogenation of ethanol under mild conditions. The deactivation of catalyst was investigated toward different conditions. Effects of reaction condition including different reaction temperatures of 300, 350, and 400 °C on the deactivation behaviors were determined. The results indicated that the operating temperature at 400 ºC significantly retained the lowest change of ethanol conversion, which favored in the higher temperature. After running reaction, the physical properties as pore size, surface area, and pore volume of spent catalysts were decreased owing to the coke formation, which possibly blocked the pore that directly affected to the difficult diffusion of reactant and caused to be lower in catalytic activity. Furthermore, a slight decrease in either acidity or basicity was observed owing to consumption of reactant at surface of catalyst or chemical change on surface caused by coke formation. Therefore, it can remarkably choose the suitable operating temperature to avoid deactivation of catalyst, and then optimize the ethanol conversion or yield of acetaldehyde.

scholarly journals HIDROLISIS MINYAK JARAK PAGAR MENJADI ASAM LEMAH BEBAS MENGGUNAKAN KATALIS CaO

2016 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Abdulloh Abdulloh ◽  
Alfa Akustia Widati ◽  
Faiz Tamamy
Keyword(s):  
Catalytic Activity ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Surface Area ◽  
Jatropha Curcas ◽  
Catalyst Deactivation ◽  
Economic Value ◽  
Jatropha Curcas Oil ◽  
Base Site

AbstrakTelah dilakukan hidrolisis minyak jarak pagar (Jatropha curcas oil: JO) menggunakan katalis CaO. Reaksi ini dimaksudkan untuk meningkatkan nilai ekonomis minyak jarak pagar selain biodiesel. Katalis CaO dikalsinasi terlebih dahulu pada suhu 800ᵒC untuk menghindari terjadinya deaktivasi katalis oleh terbentuknya CaCO3. Pada penelitian ini dilakukan karakterisasi katalis CaO meliputi struktur kristal CaO, luas permukaan, jumlah situs basa dan kekuatan kebasaan serta aktivitas katalitiknya. Hasil penelitian menunjukkan, katalis CaO memiliki luas permukaan 26,451 m2/g, kekuatan situs basa (pKB) pada daerah 7,2 < pKBH CaO < 15,0. Hasil uji aktivitas katalis CaO pada reaksi hidrolisis CJO diperoleh konversi CJO menjadi asam lemak bebas (free fatty acid: FFA) sebesar 77,58% pada waktu 60 menit. Kata kunci: hidrolisis, minyak jarak pagar (JO), free fatty acid (FFA), CaO dan  situs basa   AbstractHydrolysis of Jatropha curcas oil has been carried out using CaO as a catalyst. This reaction is intended to increase the economic value besides biodiesel. CaO catalyst was calcined at a temperature of 800 oC to avoid catalyst deactivation by formation of CaCO3. In this research include the characterization of catalysts CaO crystal structure, surface area, the number of base sites and the strength of basicity and catalytic activity. The results of the analysis showed that CaO catalyst has a surface area of 26.451 m2/g, the number of base sites of 221.77 mmol/g and the strength of base sites (pKBH)  in the range of 7.2  < pKBH CaO < 15.0. From catalytic activity test showed that that the use of the catalytic activity of CaO catalyst in the hydrolysis reaction CJO into free fatty acids (FFA) as much as 77.58% for 60 minutes. Keywords: hydrolysis, Jatropha curcas oil (JO), free fatty acid (FFA), CaO and base site

Multi Objective Optimization of a Methane Steam Reforming Reaction in a Membrane Reactor: Considering the Potential Catalyst Deactivation due to the Hydrogen Removal

2017 ◽  
Vol 16 (2) ◽  
Author(s):  
Marjan Alavi ◽  
Reza Eslamloueyan ◽  
Mohammad Reza Rahimpour
Keyword(s):  
Steam Reforming ◽  
Membrane Reactor ◽  
Pareto Front ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Optimal Solution ◽  
Methane Steam Reforming ◽  
Nsga Ii ◽  
Hydrogen Recovery ◽  
Methane Steam

AbstractSteam reforming of methane (SRM) is an important stage of hydrogen production. Using a membrane reactor (MR) to separate the produced H2positively affects CH4conversion by shifting the equilibrium. This H2removal increases the risk of coke formation in the process. In this study, the influence of different parameters such as Damkohler’s number (Da) and permeation number (θ) on CH4conversion and H2recovery are investigated. In order to find the optimum condition for this MR in which CH4conversion, H2Recovery are maximized and the risk of coke formation is minimized, the elitist non-dominated sorting genetic algorithm (NSGA-II) is employed to achieve the Pareto front in a three objective space. The single optimal solution is selected from Pareto front by TOPSIS decision making method. In the optimized condition methane conversion and hydrogen recovery are improved about 19.8% an 6.8%, respectively. Also, the risk of coke formation in the MR is reduced.

scholarly journals Comparative Study of Ni-W /CeO2, Ni-W /y-Al2O3 and Ni-W /HT Catalysts for H2 Production by Steam Reforming of Bioethanol

Quimica Hoy ◽  
2011 ◽  
Vol 2 (1) ◽  
pp. 3
Author(s):  
Paz Hernández ◽  
Arturo Fernández ◽  
Sarah Messina
Keyword(s):  
Catalytic Activity ◽  
Fuel Cell ◽  
Hydrogen Production ◽  
Comparative Study ◽  
Steam Reforming ◽  
Carbon Deposition ◽  
Nickel Content ◽  
H2 Production ◽  
Good Stability ◽  
Steam Reforming Of Ethanol

Ni-W catalysts supported on CeO2,Al2O3 and hydrotalcite (HT) were studied in the steam reforming of ethanol at 500-650ºC. The CeO2 and HT were synthesized by impregnation and direct coprecipitation methods, respectively. Commercial Al2O3 was used. Nickel content was varied from 10, 15 and 30% with 1% W. The catalyst that presented the highest catalytic activity and selectivity to hydrogen was 10% Ni-W/HT. Conversion to ethanol was 100% and selectivities to H2, CH4, CO2 and CO were 75, 5.78, 0.37 and 18.85%, respectively, at a temperature of 500 ºC. Moreover, these catalysts showed good stability with respect to carbon deposition and low selectivity towards C2H4 production. These are desirable features for catalysts to be used in hydrogen production for fuel cell applications.

An analytical microscopic study of metals in fluidized catalytic cracking catalyst

1986 ◽  
Vol 44 ◽  
pp. 854-855
Author(s):  
Clifford S. Rainey
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Acid Sites ◽  
Y Zeolite ◽  
Fcc Catalyst ◽  
Fluidized Catalytic Cracking ◽  
High Regeneration

The spatial distribution of V and Ni deposited within fluidized catalytic cracking (FCC) catalyst is studied because these metals contribute to catalyst deactivation. Y zeolite in FCC microspheres are high SiO2 aluminosilicates with molecular-sized channels that contain a mixture of lanthanoids. They must withstand high regeneration temperatures and retain acid sites needed for cracking of hydrocarbons, a process essential for efficient gasoline production. Zeolite in combination with V to form vanadates, or less diffusion in the channels due to coke formation, may deactivate catalyst. Other factors such as metal "skins", microsphere sintering, and attrition may also be involved. SEM of FCC fracture surfaces, AEM of Y zeolite, and electron microscopy of this work are developed to better understand and minimize catalyst deactivation.

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