Cyclohexane Dehydrogenation Using an Economical Iron Catalyst: Influence of Alumino-Silicate Structure on the Catalytic Activity

The effect of mixing both local Egyptian hematitic ore and activated aluminosilicate material (bentonite clay) on the dehydrogenation activity of the former was studied.

Three mixtures were prepared in which bentonite percentages were 10, 20, and 40 wt%. Cyclohexane used as a model reactant for the catalytic dehydrogenation reaction carried out in catalytic flow system within reaction temperature ranged from 150 to 500°C in the presence of hydrogen stream (75 mL/min) and at constant space velocity 3.71 h^-1.

The results obtained indicated that in spite of the drop in the selectivity of the local material toward benzene formation by clay addition, a distinct increase in the benzene yield was observed. The maximum conversion attained ∼28.14% at reaction temperature 500°C using a mixture containing 20 wt% activated bentonite.     

Oxidative Dehydrogenation of Methanol on Chromium Oxide/Montmorillonite K10 Catalysts

Abstract

Methanol conversion was carried out on a mesoporous material—chromia/montmorillonite K10 (MK10)—in a pulse microcatalytic system. Methanol was converted to formaldehyde and ethylene by two different mechanisms. Methanol dehydrogenation increases by increasing reaction temperature (300–400°C) and as chromia loading decrease. On the other hand, the dehydration of methanol occurs at a higher temperature (400–500°C) and as chromia loading increase, 3–18% Cr. Redox and exposed nonredox Cr³⁺ are responsible for formaldehyde formation. There is a relationship between increased C₂H₄ production and the increase of Cr⁶⁺ phase according to the acidity of chromia catalysts 34 and 76 μL tert-Butylamine/g catalyst for 3% Cr and 18% Cr, respectively. Formaldehyde formation is diffusionally controlled at high temperatures (400–500°C) and kinetically controlled at a lower reaction temperature (300–400°C), while methanol dehydration to ethylene is surface reaction controlled at 400–500°C.     

Study on the Processes for Lubricant Base Oil from Oman and Cabinda Blended Crude Oil No. 3 Fraction

Abstract

The dealing quantity of crude oil increases, and the lube feedstock changes frequently. Enhancing the quality and yield by optimizing the processes used for lubricant base oil is currently one of the major challenges that refineries are facing to make them profitable. Acetone-benzoyl dewaxing, furfural refining, and clay finishing are selected and optimized to process lubricant base oil. For the acetone-benzoyl dewaxing process recommended, solvent-to-oil ratio (STO) is 2.5, solvent component ratio (methyl ethyl ketone to methyl benzene) is 0.8, and dewaxing temperature is ?25°C. For the furfural refining process recommended, solvent-to-oil ratio is 3.0 and refining temperature is 90°C. The finishing oil treated with 4 wt% adsorbent clay at 155°C can meet the color and oxidation stability requirements of a marketable product. Group analysis, elemental analysis, and infrared (IR) spectra show that in optimized base oil, the saturate content is high (95 wt%), carbon–hydrogen ratio is high, and basic nitrogen content is 0.63 wt%; branching degree is suitable. ¹H nuclear magnetic resonance (¹H-NMR) and ¹³C-NMR spectra indicate that isoparaffin content is high; average number of carbon atoms is 25.85; the branched chain is located in the eighth carbon; there are large numbers of S-1, S-2, and S-11 molecules in base oil; and there are interactions among base oil molecules, but the intensity is different.     

The Aromatization of Different FCC Naphtha Fractions over a P-Zn/HZSM-5 Catalyst

Abstract

The aromatization reaction performance of P-Zn/HZSM-5 catalyst was investigated on a fixed bed reactor using five fluid catalytic cracked (FCC) gasoline fractions (<100°C, 50°C–100°C, <120°C, 75°C–120°C, and full fraction) as feedstock, and the effect of feedstock on aromatization is discussed. The results showed that the activity and stability of P-Zn/HZSM-5 catalyst for the aromatization of the 50°C–100°C fraction were high in definite reaction conditions. After 16 hr, the content of olefin and aromatics in liquid product were 5.23 and 79.9%, respectively. The liquid product of low olefin and high aromatics was obtained. The distribution of benzene, toluene, and xylene in liquid product of 50°C–100°C fraction was investigated during aromatization, and the result showed that the toluene content was maximum among the three aromatics contents, the benzene content was minimum at the beginning of the reaction, xylene content became maximum, and benzene was still minimum after reacting for 20 hr. The content of C₉ ⁺ aromatics increased at the first stage of the reaction and then decreased with the increasing reaction time.     

Physical mixture of MCM-41/ZSM-5 as an active catalyst component for maximization of propylene in Catalytic cracking of VGO

The performance of a novel catalyst additive containing highly porous MCM-41 and ZSM-5 zeolite was investigated using a commercial equilibrium FCC catalyst in catalytic cracking of vacuum gas oil. The catalytic tests were assessed in a fixed-bed microactivity test unit at reaction temperatures 500–620 °C. The highest propylene yield of 23.8 wt% was achieved at 600 °C. The propylene yield increased from 14.49 wt% to 23.8 wt% when the temperature rose from 500 to 600 °C; however the gasoline yield fell from 22.47wt% to 16.49 wt% by increasing the temperature from 580 °C to 620 °C, respectively.     

Removal of Naphthenic Acids of a Second Vacuum Fraction by Catalytic Esterification

Abstract

This article introduces a catalytic esterification process to reduce the acid number of a high acid content petroleum fraction. The fraction was treated with methanol under conditions sufficient to form the naphthenic acid esters. In this way, the acid number of the petroleum fraction could be lowered. SnO could accelerate petroleum oil esterification. The acid removal ratio was much higher in the presence of SnO than without it. The optimal reaction conditions were: reaction temperature 300°C, the quantity of methanol in oil was 5.0 wt%, the quantity of catalyst SnO was 4.0 wt%, and a longer reaction time was preferable.     

Production of Lubricating Base Oil Using a Moist SiO2/γ-Al2 O3 Catalyst

Abstract

The catalyst SiO₂/γ-Al₂ O₃ treated by micro-wetness air to produce lubricating base oil was studied in this article. The satisfactory reaction temperature, the treatment temperature, and the proper content of active composition was researched. Under the best reaction conditions with a reaction temperature of 170°C, a reaction pressure at 6.0 Mpa, the volume velocity at 0.5 h^?1. The polymerization of α-olefin was performed at a microreactor and produced lubricating base oil with the kinetic viscosity at 38.19 mm² · s^?1, the bromine number at 5.78 g(Br) · (100 g)^?1, and the pour point at ?43.0°C. Then the structure of the catalyst was determined by Brunauer, Emmett and Teller (BET) technology. The result shows that when the optimal micro-wetness air was 45°C, the reaction temperature was 800°C, and the amount of active composition was 12%, and the catalyst has high catalytic activity and wide market prospect.     

Catalytic Dehydration of Alcohols Using Thermally Pretreated Manganese Material

Abstract

The effect of thermal pretreatment on manganese material properties was investigated via XRF, DSC, XRD, MIP, and surface acidity measurements. The catalytic activity toward dehydration of different alcohols ethanol (in comparison with synthetic manganese catalyst), 1-propanol and 1-butanol was also carried out in a catalytic flow type system in the presence of hydrogen stream under atmospheric pressure with reaction temperatures ranging from 200–550°C and at different space velocities between 0.46–15.40 h^?1. The results showed an agreement between manganese calcined material and the prepared catalyst in the optimum reaction temperature required for the dehydration of ethanol to ethylene, as well as the selectivity values. Data showed decrease in total dehydration conversion percentage in the order ethanol > 1-propanol > 1-butanol.     

STUDY ON COKING KINETICS OF CHINESE GUDAO VACUUM RESIDUE

ABSTRACT

Using a molten metal bath as heat source of reaction, the coking kinetics of Gudao vacuum residue in temperature ranges of 400 – 440°C and 460–500°C were studied and kinetic models were developed. The order of reaction, pre-frequency factor and apparent activation energy of thermal-cracking were determined as 1.0, 7.853 × 10¹⁰ min^?1 and 175.3KJ/mol respectively. The results laid a solid foundation for technological computation, reconstruction and design of the tubular furnace using the residuum as its feedstock.     

Slurry-phase catalytic hydrocracking of mazut (heavy residual fuel oil) using Ni-bentonite

Abstract

In this work, Ni-bentonite catalyst was synthesized through exchange method. The synthesized catalyst and the pristine clay were characterized by XRD, XRF, TGA/TDA, TEM, EDX-mapping, nitrogen adsorption-desorption at ?196?°C, H₂-TPD and NH₃-TPD. The catalytic efficiency of the dispersed nickel catalyst toward the hydrocracking of mazut (heavy residual fuel oil) under reduced pressure has been evaluated. The experimental results showed increasing yield of middle distillate fraction to 71?wt.% as the reaction temperature raised to 430?°C under pressure 2.0?MPa.     

COMPARATIVE REACTION STUDY OF METHYLCYCLOHEXANE AND 3-METHYLHEXANE IN H2 AND N2 ON Pt/Al2O3 CATALYST

ABSTRACT

The reaction of methylcyclohexane and 3-methylhexane were studied in a pulse microcatalytic reactor using H₂ and N₂ carriers on Pt/Al₂O₃ catalyst at temperatures from 350 to 500°C, contact times (W/F) of 1.25 × 10^?3–3.75 × 10^?3 g min/ml and a total pressure of 4.0 kg/cm². In N₂, there was complete conversion of methylcyclohexane to methane, benzene and toluene while similar products were produced for 3-methylhexane, albeit with diminished conversion level. In H₂, methane was produced from 3-methylhexane conversion while aromatization without demethylation was obtained in addition to some cracking for methylcyclohexane at the low temperature range (350–400°C); a higher temperature range (460–500°C) resulted in complete fragmentation for methylcyclohexane. In H₂–N₂ mixtures, the presence of N₂ of not less than 50% in the carrier gas stream yielded an aromatic catalyst at conditions where only cracking activity was previously evident. The differences in product distribution and/or product types for the two reactants in H₂ and N₂ suggest a different reaction mechanism for both reactants.     

Ammonium perchlorate decomposition: Neat and solution1

Abstract

The thermal decomposition of ammonium perchlorate (AP) was examined over a broad temperature range (215°C to 385°C) in solution and condensed phase. Over the entire temperature range, the decomposition, as monitored by loss of ammonium ion, appeared first-order out to 70% decomposition. Up to about 350°C the decomposition of AP in methanol (5wt% AP) proceeded at a rate similar to neat AP, but the AP in aqueous solution (20wt%) decomposed considerably slower than the neat material. Activation energies and frequency factors were determined for each experimental condition. In addition, decomposition products, both gaseous and condensed phase, were identified and quantified. For neat AP decomposition, the following reaction stoichiometries were determined.

At low temperatures, decomposition of ammonium perchlorate in methanol proceeded at a similar rate to that of neat AP. In contrast to decomposition of neat AP, the only nitrogen-containing decomposition product was nitrogen gas, while chlorine appeared only as chloride. The presence of CO and CO₂ as decomposition gases and chromatographic analysis of the solvent indicated interaction between methanol and AP. The decomposition of AP in water was slowed, but product distribution was not significantly different than that of neat AP.     

Effect of Severity on Hydrotreating of Demetallized Oil Monitored by 1H-NMR Spectroscopy

Abstract

A study on aromatic hydrogenation of demetallized oil has been carried out using a commercial catalyst under pilot plant reaction conditions similar to those found in industrial processes. The feedstock was contacted with the catalysts in a trickled bed reactor unit at 330°C, 350°C, and 370°C. A combination of physicochemical characterization of feed and products and ¹H-NMR spectra was used to monitor changes in the aromatic fractions caused by variation in reaction temperature. Analysis of the ¹H-NMR spectra, along with the quantitative variation in the areas of the resonance lines, showed that the diaromatics with relatively long alkyl changes present in the lightest distillation cuts of the products were highly hydrogenated. In contrast, smaller changes in aromaticity in the heaviest fractions were observed under the same conditions. A limit of about 2 wt% of the integrals corresponding to the diaromatic+ species suggests a thermodynamical limitation of hydrogenation under the studied reaction conditions.     

SUPERCRITICAL AND CATALYTIC FLUID EXTRACTIONS OF TEA WASTES

Abstract

Air dried and ground tea waste was subjected to supercritical and catalytic fluid extraction by using water or acetone as solvent at different temperatures. The most important reactions variables were temperature and ratio of catalyst to the solid sample. The yields of the catalytic fluid reaction have been increased from 70.3 % to 92.4 % as the temperature increased from 230 °C to 340 °C by using water as solvent. The yield of extract was obtained from non catalytic supercritical water extraction was about 50.0 % at380°C.     

COKE CHARACTERISTICS IN RELATION TO THE COLLOIDAL. MATTER OF PETROLEUM FOR THERMAL. PROCESSES

Abstract

The purpose of this work is to research the characteristics of the production of coke in thermal and hydrothermal cracking from residual oils and their deasphalted oils Using ethyl acetate, because it allows the elimination of both resins and asphaltenes (colloidal matter) from the parent oil in only one step. This improves the deasphalted oil as coke precursors and basic nitrogen compounds present in the resin fraction are practically eliminated.

A 104 ml batch autoclave reactor with a cooling system was used for the thermal and hydrothermal cracking experiments. This reactor can withstand temperatures of up to 500^°C, pressures of 500 bar and a rocking velocity of 1 Hz. The influence of the temperature was investigated at 400, 425 and 450^°C and at 0, 20, 40, 80,     

Upgrading of Mumbai High vacuum residue

Upgrading of waxy Mumbai High vacuum residue was carried out at four different temperatures, viz. 430, 445, 460, and 475?°C in an autoclavable reactor. The temperature difference between the material at the wall and at the centre of the reactor was found to be as low as 0^οC and as high as 10^οC depending upon rate of coke formation at different severities. Maximum coke formation (23.31?wt%) was found at 475?°C and for the reaction time of 60?min. Maximum liquid and gas yield was found to be 55.96?wt% and 16.9?wt%, respectively at 475?°C and for the reaction time of 90?min.     

Dehydrogenation of n-butane on the industrial microspherical chromia-alumina catalyst AOK-73-24 in a membrane reactor

The basic features of the catalytic membrane dehydrogenation of n-butane have been studied in a reactor with membrane modules based on Pd/Ag foil of 9.3 and 30 μm thickness and in the absence of the membrane (temperature, 500–550°C; feed space velocity, 150–1200 h^?1). It has been shown that in the absence of the membrane, the dehydrogenation of n-butane occurs in the kinetic region. The membrane thickness has a significant effect on the performance of the catalytic membrane reaction, presumably, because of the difference in the rate of H₂ withdrawal from the reaction mixture. In the reactor with the 9.3-μm thick Pd/Ag-foil, the reaction is controlled by the H₂ formation rate. As the thickness of the palladium foil is increased to 30 μm, the reaction proceeds to the diffusion region, thereby resulting in both enhancement of selectivity for butenes and a reduction of the yield of hydrocarbon deposits.     

An Orthogonal Method for Aromatization Reactions of Shenghua FCC Gasoline

Abstract

Using a confined fluidized bed reactor and aromatization catalysts (LBO-A and LBO-16), the aromatization performance of Shenghua fluid catalytic cracking (FCC) gasoline has been studied in an orthogonal method. The experimental results reveal that the optimum reaction condition for the light oil yield was reaction temperature 420°C, WHSV 40 h^?1, mass ratio catalyst to oil 4 and 75% LBO-A and 25% LBO-16; the optimum reaction condition for aromatics amount in the light oil was reaction temperature 420°C, WHSV 30 h^?1, mass ratio catalyst to oil 5 and 65% LBO-A and 35% LBO-16, the olefin content is remarkably reduced from about 54.7% to 12.8% and 8.7% (by mass), respectively, at the same time the reaction mechanism of aromatization reaction is put forward based on the experimental result.     

Ammonium perchlorate-based molecular perovskite energetic materials: preparation,characterization, and thermal catalysis performance with MoS2

ABSTRACT

In this study, ammonium perchlorate (AP)-based molecular perovskite structural high-energetic materials (H₂dabco)[NH₄(ClO₄)₃] (DAP) were fabricated and their catalytic performance upon the addition of MoS₂ nanosheets was investigated. The DAP samples were succesfully prepared via a self-assembly reaction and their morphology and structure were characterized via scanning electron microscopy, X-ray diffractometry, and Fourier transform infrared spectroscopy. The thermal decomposition performance of a pure DAP sample and of a mixture of DAP with MoS₂ nanosheets were analyzed via differential scanning calorimetry. The results show that DAP has a high thermal stability at its initial decomposition temperature of 319.8°C, and that its apparent decomposition heat measures 4199 J/g. This value is higher than for AP (829.7 J/g). Furthermore, the thermal decomposition peak temperature of DAP upon the addition of 1 wt% and 3 wt% MoS₂ nanosheets decreases from 394.4°C to 343.3°C and 328.8°C, respectively. The investigation of the catalysis thermal performance of DAP may foster its practical application in composite propellant.     

Polarization and Polarizability of the Binary Mixtures of Tetraethylene Glycol With Benzene and Toluene at 20°C and 30°C

Abstract

The refractive index of the binary mixtures of tetraethylene glycol (TETEG) with benzene and toluene at 20°C and 30°C and atmospheric pressure have been measured at the whole composition range of mixtures. The polarizabiltiy (α), atomic polarization (P_a), solvated radii (r), and excess refractive indices (n^DE) were calculated and represented in figures versus concentration.