Catalyst Calcination Temperature Research Articles

Calcium-Loaded Municipal Sludge-Biochar as an Efficient and Stable Catalyst for Biodiesel Production from Vegetable Oil.

In this contribution, biochar from municipal sludge was used as a novel matrix for the synthesis of a series of calcium-based heterogeneous catalysts toward biodiesel production. Their catalytic activity was investigated in terms of catalyst loading and calcination temperature during preparation, in addition to the transesterification parameters including the methanol/oil molar ratio, reaction time, and catalyst amount. The highest biodiesel yield up to 93.77% was achieved with the 30Ca/A-SBC-700, and it maintained as high as 84.9% even after 10 cycles of a consecutively alternating catalysis and regeneration process. It was revealed that the porous municipal sludge biochar and autologous SiO2 were accountable for the superior stability of the present catalyst. This work may provide a new path to value-added valorization of sludge waste and also a renewable and efficient catalyst for biodiesel production at a low cost.

Synthetic natural gas production from the three stage (i) pyrolysis (ii) catalytic steam reforming (iii) catalytic hydrogenation of waste biomass

Synthetic natural gas (methane) production was systematically investigated by optimizing various operating parameters using a three stage (i) biomass pyrolysis (ii) catalytic steam reforming (iii) catalytic hydrogenation reactor system. Several operating parameters were optimized including catalytic steam reforming temperature, steam weight hourly space velocity (WHSV), catalytic hydrogenation temperature and hydrogen gas space velocity. In addition, the influence of different metal catalysts (Ni/Al2O3, Fe/Al2O3, Co/Al2O3, and Mo/Al2O3), catalyst calcination temperature, catalyst metal loadings, and different catalyst support materials (Al2O3, SiO2, and MCM-41) was carried out specifically to optimize catalytic hydrogenation in the third stage reactor. The highest methane yield of 13.73 mmoles g−1biomass (22.02 g CH4 100 g−1biomass) was obtained with a second stage catalytic steam reforming temperature of 800 °C over a 10 wt% Ni/Al2O3 catalyst and with a steam WHSV of 5 mL h−1 g−1catalyst together with a third stage catalytic hydrogenation temperature of 350 °C over a 10 wt% Ni/Al2O3 catalyst with added hydrogen gas space velocity of 2400 mL h−1 g−1catalyst.

Fibrous La2Zr2O7 pyrochlore-supported Ni nanocatalysts for methane reforming

This study aims to investigate La2Zr2O7 pyrochlore-supported Ni nanocatalysts prepared by electrospinning and subsequent heat treatment. The solid solubility of Ni in La2Zr2O7 forms an interaction between NiO and La2Zr2O7 supports, which improves Ni dispersion and therefore increases catalytic activity during methane partial oxidation. The catalyst activity increased with Ni content up to 7 wt%. A further increase of the Ni content decreased the activity due to the limited solubility. The catalyst calcination temperature affected the interaction and hence the catalytic activity, and the optimal calcination temperature was 1000 °C. The Ni/La2Zr2O7 catalyst was compared with a conventional Ni/Al2O3 catalyst in term of the interaction. NiAl2O4 formation caused a strong interaction between Ni and Al2O3 supports, resulting in high reduction temperatures and low reducibility. In contrast, the limited solubility of Ni in La2Zr2O7 supports formed a more effective interaction, demonstrating the higher reducibility and catalytic performance. Therefore, an effective interaction between active catalyst and support is crucial to achieve high catalytic performance.

Ni/La2O3 and Ni/MgO–La2O3 catalysts for the decomposition of NH3 into hydrogen

The decomposition of NH3 for hydrogen production was studied using Ni/La2O3 catalysts at varying compositions and temperatures prepared via surfactant-templated synthesis to elucidate the influence of catalyst active metal content, support composition and calcination temperature on the catalytic activity. The catalytic performance of all samples was studied between 300 and 600 °C under atmospheric pressure. The catalytic activity of the sample were as follows: 10Ni/La2O3-450 > 10Ni/La2O3-550 > 10Ni/La2O3-650 ≈ 10Ni/La2O3-750 ≈ 10Ni/La2O3-850. The excellent activity (100%) of 10Ni/La2O3-450 could be due to the high surface area, basicity strength and concentration of surface oxygen species of the catalyst as evidenced by BET, CO2-TPD and XPS. In addition, to adjust the activity of the catalyst support, the molar ratios of Mg and La were varied (1:1, 3:1, 5:1, 7:1 and 9:1). The 5Ni/5MgLa (5:1 M ratio) was found to be the most active (100%) relative to other Ni/MgLa formulations. Furthermore, the Ni content in the Ni/5MgLa sample was adjusted between 10 and 40 wt%. Increasing the Ni content of the catalysts increased NH3 conversion with the 40 wt% Ni formulation demonstrating complete NH3 conversion at 600 °C and a high gas hourly space velocities (GHSV) (30,000 mL∙h−1∙gcat−1).

Catalytic study of Ni/Ce/Al2O3 and Ni/Ca/Al2O3 on the removal of naphthenic acid from petroleum crude oil utilizing sodium thiocyanate in ethanol

The naphthenic acids (NAs) present in the crude oil can lead to the corrosion problems in oil refinery equipment apart from reduces the performances of the oil. In this study, the method to remove NA were done by means of extraction using sodium thiocyanate in ethanol with the aid of Ni/Ca/Al2O3 and Ni/Ce/Al2O3 catalysts at 27 °C reaction temperature. The catalyst was prepared by incipient wetness impregnation method (IWI) and calcined at three different temperature, 800, 900 and 1000 °C respectively. The efficiency of the extraction was affected by the catalyst calcination temperature. Both catalysts calcined at 800 and 900 °C gave total acid number (TAN) value more than 1 mg KOH/g while by using Ni/Ca(10:90)/Al2O3 and Ni/Ce(10:90)/Al2O3 calcined at 1000 °C the TAN value were reduced to 0.28 and 0.65 mg KOH/g respectively. Brunauer-Emmett Teller (BET) result shows both catalysts have large surface area that provide more reaction cites when calcined at 1000 °C. X-ray Diffraction Spectroscopy (XRD) analysis of Ni/Ca/Al2O3 catalyst revealed that the active site was dominated by the Al2O3 species while CeO2 was the active site for Ni/Ce/Al2O3 catalyst. In conclusion, both catalysts reduced the TAN value of acidic crude oil efficiently.

Design of a comprehensive experiment of the synthesis of biodiesel catalyzed by CaO

An applied chemistry comprehensive experiment has been designed using CaO for synthesis of biodiesel. Effects of calcination temperature, methanol concentration, reaction temperature, reaction time and amount of catalyst on transesterification reaction are investigated. Based on experiment, the relationship between the catalyst structure and its properties was analyzed. Furthermore, this experiment can cultivate student's abilities of analyzing and solving problem. And it can build up the innovation consciousness, competition and team spirit of students. At the same time, the biodiesel and its preparation are line with the development requirements of green chemistry, so that students can establish environmental protection concept.

The Effect of Calcination Temperature of RuTi Catalysts on the Reaction Activity of NH 3 -SCO

The Effect of Calcination Temperature of RuTi Catalysts on the Reaction Activity of NH 3 -SCO

Preparation of a novel and highly stable Al-Fe loaded sepiolite catalyst for the CWPO of methyl orange: Optimization of physicochemical parameters, kinetics and thermodynamics studies

Al-Fe loaded sepiolite catalysts with different active metal ratio have been synthesized using a Turkish sepiolite sample from Eskişehir region. Liquid phase catalytic oxidation of methyl orange azo dye has been carried out over Al-Fe/sepiolite catalysts using hydrogen peroxide as oxidant. The catalytic studies are performed in a glass reactor under atmospheric pressure by semi-batch operation. The effects of several parameters such as catalyst amount, metal loading, calcination temperature, pH, H2O2 concentration, reaction temperature and time on the methyl orange elimination have been examined. The elimination rate of 90.68% was achieved when studied with the catalyst with 8% active metal ratio (SepAlFe8) at pH 3.7 and 25°C. Kinetics studies show the degradation of methyl orange over the SepAlFe8 catalyst could be expressed by the pseudo-first-order reaction kinetics (k1 = 0.0049 min-1 at 25°C). The activation energy (Ea) of the reaction over this catalyst is foundas 29.48 kJ mol-1. It was also found that the catalytic oxidation process is endothermic (ΔH = 26.99 kJ mol-1) and nonspontaneous (ΔG = 96.72 kJ mol-1 at 25°C). The catalyst is chemically stable and reusable with low release of iron.

Activation of Cement Clinker as Catalysts for Transesterification Reaction of Palm Oil Off Grade to Biodiesel

Calcium oxide (CaO) is a heterogeneous solid base which is generally used as a catalyst in making biodiesel. It is mainly obtained from cement clinker and activated through calcination method. The purpose of this study was to determine the effect of using cement clinker catalyst on the yield of the biodiesel. A batch reactor with a condenser was used in making the biodiesel under favorable conditions such as calcination temperatures of 700 °C, 750 °C and 800 °C, time of 5, 6 and 7 hours, and catalyst concentration of 1%-w, 2%-w, and 3%-w oil. The analysis involved X-Ray Diffraction (XRD) and Brunauer-Emmett-Teller (BET) for catalysts and Gas Chromatography-Mass Spectrometry (GC-MS). The catalyst calcination temperature determined the optimum conditions. From this study, the conditions necessary for transesterification reaction include the mole ratio of methanol/oil of 6 to 1, the temperature of 70 °C for 2 hours and 700 °C for 5 hours, and catalyst dosage of 2% by weight. Under these conditions, the yield of the biodiesel was 84.26%. Additionally, at the calcination temperature of 800 °C for 7 hours and catalyst dosage of 3% by weight, the yield of the biodiesel was 76.84%. CaO, SiO2, 2CaO.SiO2 and 3CaO.SiO2 were found in the catalyst through XRD analysis. The specific surface areas of the catalyst were 25,497 m2/g (700 °C/5 hours) and 35,879 m2/g (800 °C/7 hours) through BET analysis. According to the GC-MS analysis, the main components of the biodiesel include methyl palmitate, methyl oleate, and methyl stearate.

Structure‐Activity Relationships of Au/Al2O3 Catalyst for the Selective Oxidative Esterification of 1,3‐Propanediol and Methanol

Abstract1.5 wt. % Au/Al2O3 catalysts were prepared using the deposition‐precipitation or colloid‐deposition method and calcined at different temperatures for the selective oxidative esterification reaction of 1,3‐propanediol and methanol to form methyl 3‐hydroxypropionate (3‐HPM). The catalysts were characterized by nitrogen adsorption, transmission electron microscopy (TEM), X‐ray diffraction (XRD), UV‐Vis diffuse reflectance spectroscopy, X‐ray photoelectron spectra (XPS), CO2 temperature‐programmed desorption (CO2‐TPD) and NH3 temperature‐programmed desorption (NH3‐TPD). The effect of the calcination temperature of the catalyst prepared by the deposition‐precipitation method on the catalytic performance for the selective oxidative esterification of 1,3‐propanediol was studied. The results showed that the conversion of 1,3‐propanediol and the selectivity of 3‐HPM increased at first and then decreased with the increase of the calcination temperature of catalyst. The highest conversion of 1,3‐propanediol and selectivity of 3‐HPM at the optimal calcination temperature of 350 °C were 92.0% and 88.5%, respectively. Considering the effects of preparation method and calcination temperature, it could be concluded that the metallic Au nanoparticles with appropriate particle size in coordination with the suitable amount of weak and middle acid and base sites, were favorable to the oxidative esterification of 1,3‐propanediol and methanol to 3‐HPM. Moreover, we found that the 1.5 wt. % Au/Al2O3 catalyst could be effectively recovered without obvious decline of the catalytic properties.

Morphological and Electrical Characteristics of Multi‐walled Carbon Nanotubes and their Composites Depending on Catalyst Calcination Temperature

External shape, specific surface area, and thermogravimetric analyses of the Fe‐based catalysts on the Al(OH)3 and multi‐walled carbon nanotubes (MWCNTs) were performed. The physicochemical changes in the MWCNT composites were found to be correlated with the catalyst calcination temperature. When the catalyst calcination temperature increased from 300 to 700 °C, the electrical conductivity improved. The reduced weight of the MWCNTs after calcination was determined to be due to the removal of water remaining in the catalyst, resulting in an improved specific surface area of the MWCNTs and increased synthesis yield. Additionally, it is expected that the removal of water from the catalyst will be beneficial in the mass production of multi‐walled carbon nanotubes because it can prevent the fume phenomenon, which reduces synthesis yield.

Upgrading lignin bio-oil for oxygen-containing fuel production using Ni/MgO: Effect of the catalyst calcination temperature

Biofuel production from renewable resources is becoming an increasingly attractive option given the depletion of fossil fuels and the environmental problems caused by the excessive use of unsustainable energy resources. In this study, an efficient approach is provided for high-quality oxygen-containing fuel production from renewable lignin bio-oil. The results demonstrate that the calcination temperature has a remarkable effect on the catalyst structure, surface Ni content and physico-chemical properties of the Ni/MgO material, all of which result in significantly different performances in the upgrading of lignin bio-oil. At 160 °C for 4 h and 3 MPa of hydrogen, a 98% lignin bio-oil model compound of guaiacol is converted with 97% cyclohexanol selectivity in the presence of 15% Ni/MgO-850. Furthermore, the optimized catalytic system is reusable and shows good catalytic performance in the upgrading of both light and heavy lignin bio-oils, indicating that it is a promising strategy for renewable lignocellulosic biomass valorization.

Methane Production from the Pyrolysis–Catalytic Hydrogenation of Waste Biomass: Influence of Process Conditions and Catalyst Type

The production of methane through the optimization of various operating parameters and the use of different catalysts has been investigated using a two-stage, pyrolysis–catalytic hydrogenation reactor. Pyrolysis of the biomass in the first stage produces a suite of gases, including CO2 and CO, which undergo catalytic hydrogenation in the presence of added H2 in the second stage. The influence of the biomass pyrolysis temperature, catalyst temperature, and H2 gas space velocity has been investigated for the optimization and enhancement of the methane yield. In addition, different metal catalysts (Co/Al2O3, Mo/Al2O3, Ni/Al2O3, Fe/Al2O3), the influence of different metal loadings, catalyst calcination temperature, and different support materials (Al2O3, SiO2, and MCM-41) were investigated. The yield of methane was linked to the properties of the catalysts including the preparation calcination temperature and support material which influenced the catalyst surface area and metal crystallite particle size by sintering. The highest methane yield of 7.4 mmol g–1biomass was obtained at a final pyrolysis temperature of 800 °C, catalyst temperature of 500 °C, and H2 gas hourly space velocity of 3600 mL h–1 g–1catayst. This optimization process resulted in 75.5 vol % of methane in the output gaseous mixture.

Hydrocracking of waste cooking oil into biogasoline in the presence of a bi-functional Ni-Mo/alumina catalyst

ABSTRACT Increasing efforts are invested to investigate alternative fuel sources that can replace conventional fuels, partially or completely. The feasibility of producing biogasoline from waste cooking oil (WCO) has been investigated. A study in which WCO was cracked over a bi-functional Ni-Mo/alumina catalyst in the presence of hydrogen gas at constant pressure has been conducted. The study was based on the hydrocracking of WCO into a liquid fuel with a carbon number range analogous to that of petroleum-derived gasoline. The impact of various reaction parameters, namely, reaction temperature, contact time, catalyst: oil ratio, Ni-loading (wt. %) and catalyst calcination temperature, have on the production of biogasoline been investigated in a series of experiments. The produced biogasoline from each experiment was characterized using GC-MS. The results revealed a maximum production of 59.50 wt. % biogasoline. This was achieved at a reaction temperature of 250°C, catalyst: oil ratio of 1:75, the reaction time of 1 h. with a catalyst loaded with 5 wt. % nickel (Ni) and calcinated at 300°C.

Production of propylene glycol (propane-1,2-diol) in vapor phase over Cu–Ni/γ-Al2O3 catalyst in a down flow tubular reactor: effect of catalyst calcination temperature and kinetic study

The modification of physicochemical characteristics of 20 wt% Cu–Ni (1:1)/γ-Al2O3 catalyst by varying the calcination temperature and its effect in vapor phase hydrogenolysis of glycerol to propane-1,2-diol was examined in packed bed down flow tubular reactor. The catalyst calcined at 400 °C rendered the highest glycerol conversion (~ 100%) and propane-1,2-diol selectivity (~ 89.5%) at 220 °C, 0.75 MPa and at the weight hourly velocity of (WHSV) of 1.3 h−1. The bifunctional nature of the new Cu–Ni bimetallic phase along with very high metal dispersion (~ 20%), lower crystallite size (≤ 20 nm) and high metal surface area ~ 30 m2 g−1 were the primary reason for the higher activity and selectivity to propane-1,2-diol. Furthermore, using a two-step reaction mechanism (glycerol dehydration to acetol and subsequent hydrogenation of acetol to propane-1,2-diol), a kinetic model was developed based on Eley–Rideal approach. The activation energies for the formation of acetol and propane-1,2-diol were calculated as 55.14 and 50.87 kJ mol−1, respectively.

Decomplexation removal of Ni(II)-citrate complexes through heterogeneous Fenton-like process using novel CuO-CeO2-CoOx composite nanocatalyst.

A novel CuO-CeO2-CoOx nanocatalyst was prepared for heterogeneous Fenton-like reaction to break the Ni2+-chelate into free Ni2+ in electroless nickel plating wastewater, followed by separation of Ni2+ in an insoluble form. The composite nanocatalysts prepared by co-precipitation method were characterized by XRD, TEM, and XPS, et al. Its catalytic activity as Fenton-like reagent was evaluated by the removal efficiency of Ni(II)-citrate after decomplexation and postprecipitation treatment. Subsequently, the effects of operating parameters on the decomplexation efficiency of the nanocatalysts were investigated including calcination temperature of catalysts, H2O2 concentration, catalyst dosage, initial pH and reaction temperature. Under optimized condition, the Ni(II)-citrate complexes (C0 = 1.0 mM) achieved the complete decomplexation (>99.9%) within 60-min reaction using 0.3 g/L of CuO-CeO2-CoOx calcined at 450 °C and 75 mM of H2O2 at pH 3.0 under 50 °C of reaction. Then, Ni2+ after decomplexation could be completely removed by the subsequent precipitation at pH 11.0. In addition, the life test of CuO-CeO2-CoOx catalyst indicated that, after recycled 10 times, its activity for decomplexation of Ni(II)-citrate decreased no more than 8%. As a result, this new heterogeneous Fenton-like process is promising for decomplexation and purification of electroless nickel plating wastewater as a sludge reduction technology.

Experimental Design and Optimization of Triclosan and 2.8-Diclorodibenzeno-p-dioxina Degradation by the Fe/Nb2O5/UV System

This study describes the experimental design and optimization of the photocatalytic reaction using the immobilized catalyst Fe/Nb2O5 in the degradation of Triclosan and 2.8-DCDD. The techniques employed to characterize the photocatalysts were: specific surface area, average pore volume, average pore diameter, photo-acoustic spectroscopy (PAS), X-ray diffraction (XRD), and scanning electron microscopy (SEM/EDS). The reaction parameters studied were pH, catalyst concentration, catalyst calcination temperature, and nominal metallic charge. The results indicated that the immobilized Fe/Nb2O5 catalysts were efficient in the degradation of Triclosan and 2.8-dichlorodibenzene-p-dioxin. The catalysts with nominal metal loading of 1.5% Fe calcined at 873 K showed the highest constant reaction rate and the lowest half-life 0.069 min−1 and 10.04 min. Tests in different matrices indicated that the photocatalytic reaction using aqueous solution containing Cl− is faster when compared with the ultrapure water matrix.

Effects of manganese content and calcination temperature on Mn/Zr-PILM catalyst for low-temperature selective catalytic reduction of NOx by NH3 in metallurgical sintering flue gas.

The effects of manganese content, carrier calcination temperature, and catalyst calcination temperature of manganese-based zirconium pillared intercalated montmorillonite (Mn/Zr-PILM) catalysts were investigated for low-temperature selective catalytic reduction of NOx by NH3 (NH3-SCR) in the metallurgical sintering flue gas. The physicochemical properties of these catalysts can be characterized by X-ray diffraction (XRD), N2 adsorption-desorption isotherm, and temperature-programmed desorption of ammonia (NH3-TPD). The 10Mn/Zr400-PILM(300) catalyst had the highest NOx conversion under excess oxygen conditions (15vol% oxygen) and reached 91.8% NOx conversion at 200°C. It was found that when the loading of manganese was 10wt.%, the catalyst had the highest catalytic activity and the manganese-active component was highly dispersed on the Zr-PILM surface. The optimal calcination temperature of the Zr-PILM was 400°C because the catalyst pore size was concentrated at 1.92nm and the catalyst had the most acidic sites. And the optimum calcination temperature of the catalyst was 300°C. This was because excessive calcination temperature promoted the manganese oxide polymerization and reduced the catalytic activity of the catalyst.

EXTRACTION OF NAPHTHENIC ACIDS FROM ACIDIC PETROLEUM CRUDE OIL UTILIZING 2-METHYLIMIDAZOLE WITH THE AID OF Ca/Al2O3 AND Ce/Al2O3 CATALYSTS

Naphthenic acids (NAs) is one of the major sources of corrosion in oil pipelines and distillation units in crude oil refineries. Removing NA compounds from crude oils is regarded as one of the most crucial processes in heavy oil upgrading. Catalytic deacidification method had been developed in order to reduce the total acid number values in crude oil. Crude oil from Petronas Penapisan Melaka had been chosen to be studied with original total acid number (TAN) of 2.43 mg KOH/g. The parameters used were different catalyst calcination temperatures, catalyst loading, reagent concentration, reaction times and reaction temperature. Acid removal agent of 2-methylimidazole in ethanol and monometallic calcium and cerium doped with alumina were used as a catalyst. The results showed that with the aid of catalyst, the TAN can be reduced to lower than 1 mg KOH/g. Catalyst of Ca/Al2O3 calcined at 900oC gave a better reduction than Ce/Al2O3 with 83.54% of TAN reduction (2.43 to 0.4) for Ca/Al2O3 catalyst and 71.19% (2.43 to 0.7) for Ce/Al2O3 catalyst. The best catalyst underwent several characterization methods such as X-Ray Diffraction Spectroscopy (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetry Analysis (TGA-DTA) for its physicochemical properties. It can be concluded that catalytic deacidification method was effective in extracting NAs from the crude oil thus lowered the TAN value to less than 1 mg KOH/g.
 Keywords: Naphthenic acids; Crude oil; Catalysts

Efficient nonthermal plasma degradation of toluene over NiO catalyst with limited NOx generation

A problem encountered during nonthermal plasma destruction of pollutants in gas streams containing air is that high levels of nitrogen oxides may also be formed as a consequence of the complex processing conditions. In the work presented herein, a post nonthermal plasma catalytic system was evaluated for removal of toluene gas. NiO/γ-Al2O3 catalysts with different NiO loadings were prepared via the traditional impregnation method and their activity determined under certain conditions. The effects of the specific input energy (SIE), catalyst calcination temperature, and NiO loading on the toluene degradation were investigated. The catalyst prepared by calcination at 450 °C showed the highest activity. The catalytic activity of the catalysts first increased then decreased with increasing NiO loading, with the maximum toluene conversion of 93 % being achieved by 1.25 wt% NiO/γ-Al2O3 at 200 ppm. Meanwhile, the amount of NOx produced during the reaction was investigated. In the reaction process, a very small amount of NOx was produced, indicating that the catalyst is green and efficient.