Batch Autoclave Research Articles

Exploring the Morphological Effect of Zeolite Beta on Catalytic Cracking of Polyethylene.

Two types of zeolite catalysts, namely, nanosized Beta-N and micrometer-sized Beta-M, were used to crack low-density polyethylene (LDPE) with three different molecular weights: 4000, 200,000, and 3,000,000. The structural and acidic properties were analyzed by N2 physisorption, transmission electron microscopy, X-ray diffraction, temperature-programmed desorption of isopropylamine (IPA-TPD), and pyridine-adsorbed FTIR. The catalytic activity was tested at 623 K and 3.5 N2 MPa in an autoclave batch reactor for PE cracking. High Mw PE required higher decomposition activation energy due to transfer limitation. Beta-N showed better activity in PE cracking than Beta-M, with PE conversion of 82.7 and 62.0% for Beta-N and Beta-M, respectively. In addition, the nanosized Beta-N exhibited quite lower activation energy of catalytic PE decomposition than Beta-M, obtained by the Kissinger method in TGA measurement. The characterization results demonstrated that the Beta-N has abundant interparticulate mesopores to provide better dispersion for the catalysts into PE melt and the proximity of the cracking active sites. These results revealed that the Beta-N catalyst shows superior activity for the cracking of polyolefins.

Production of 1,3-propanediol via in situ glycerol hydrogenolysis in aqueous phase reforming using bimetallic W-Ni/CeO2.

The production of 1,3-propanediol via in situ glycerol hydrogenolysis and aqueous phase reforming is a promising technique to ensure high product yield with shorter reaction times and lower costs, as demonstrated in this study by investigating the effect of tungsten (W) doping on Ni/CeO2 catalysts. Physicochemical properties of catalyst were determined using XRD, H2-TPR, NH3-TPD, BET, and FESEM-EDX techniques, and the catalytic performance was investigated at 230 °C, 20 bar, and 5 wt.% glycerol in an autoclave batch reactor. W doping ranging from 1-7% improved the catalyst's performance, with 3% W in 10% Ni/CeO₂ (3W10NC) achieving the highest yield (2.4%), selectivity (33.3%), and a good conversion rate (72.18%). The effect of reaction parameter on the 3W10NC catalyst showed that increasing pressure and temperature from the initial parameters had a detrimental effect on 1,3-propanediol attributed to the phenomenon called over-hydrogenolysis. Increasing the glycerol concentration to 20 wt.% also had a positive effect, resulting in the highest 1,3-propanediol yield of 22.27%. The effect of reaction time study revealed that the yield of 1,3-propanediol continued to increase steadily, reaching 38.29% after 4 h of reaction under the optimal conditions of 230 °C, 20 bar, and 20 wt.% glycerol. The kinetic study confirmed that the reaction follows first-order reaction with activation energy of 20.104 kJ mol-1. The catalyst reusability test revealed a decrease in the yield of 1,3-propanediol to 32.55%, likely due to deactivation caused by sintering and leaching, as indicated by the FESEM micrograph, EDX spectra, and NH3-TPD.

Evaluation of MgO-rich materials obtained from Ferronickel slag for CO2 sequestration

Because it has a high magnesium content, ferronickel (FeNi) slag is a potential alternative material for CO2 sequestration. The slag can be pretreated by alkali fusion with NaOH to obtain MgO-rich materials. In this study, the potential of this MgO-rich material for CO2 sequestration was investigated using MgO from FeNi slag (MgO-FS) and MgNa2SiO4 from FeNi slag (MNA). A MgO reagent (MgO-R) and FeNi slag were used as reference materials. The carbonation process was carried out using a batch autoclave with various liquid-to-solid (L/S) ratios, initial pressures, times, and CO2 concentrations. The MgO-FS effectively captured CO2 and had a carbonation performance comparable to that of MgO-R. The degrees of carbonation for MgO-R, MgO-FS, and MNA were 68.43 %, 65.53 %, and 39.40 %, respectively, when carbonation was carried out at 423 K and 8 bar with an L/S ratio of 10 mL/g and pure CO2 for 9 h. Combination of the FeNi slag alkali fusion process (1:2 FeNi slag/NaOH mass ratio, 773 K, and 4 h) with water washing and carbonation (4 bar, 423 K, 10 mL/g L/S ratio, 3 h, and pure CO2) gave a CO2 uptake efficiency of 0.119 ± 0.004 g CO2/g FeNi slag. The results of the degree of carbonation (i.e. 65.53 %), X-Ray diffraction spectra (magnesite mineral peak), and scanning electron microscope observations (magnesite crystal appearance) provide evidence that MgO-FS is an effective alternative material for indirect CO2 sequestration.

Catalyst Accessibility and Acidity in the Hydrocracking of HDPE: A Comparative Study of H-USY, H-ZSM-5, and MCM-41 Modified with Ga and Al.

Plastic pollution is a critical environmental issue due to the widespread use of plastic materials and their long degradation time. Hydrocracking (HDC) offers a promising solution to manage plastic waste by converting it into valuable products, namely chemicals or fuels. This work aims to investigates the effect of catalyst accessibility and acidity on the HDC reaction of high density polyethylene (HDPE). Therefore, a variety of materials with significant differences in both textural and acidic properties were tested as catalysts. These include H-USY and H-ZSM.5 zeolites with various Si/Al molar ratios (H-USY: Si/Al = 2.9, 15, 30 and 40; H-ZSM-5: Si/Al = 11.5, 40, 500) and mesostructured MCM-41 materials modified with Ga and Al, also with different Si/metal ratios (Si/Al = 16 and 30; Si/Ga = 63 and 82). Thermogravimetric analysis under hydrogen atmosphere was used as a preliminary screening tool to evaluate the potential of the various catalysts for this application in terms of energy requirements. In addition, batch autoclave reactor experiments (T = 300 °C, PH2 = 20 bar, t = 60 min) were conducted to obtain further information on conversion, product yields and product distribution for the most promising systems. The results show that the catalytic performance in HDPE hydrocracking is determined by a balance between the acidity of the catalyst and its structural accessibility. Accordingly, for catalyst series where the structural and textural properties do not vary with the Si/Al ratio, there is a clear correlation of the HDPE degradation temperature and of the HDPE conversion with the Si/metal ratio (which relates to the acidic properties). In contrast, for catalyst series where the structural and textural properties vary with the Si/Al ratio, no consistent trend is observed and the catalytic performance is determined by a balance between the acidic and textural properties. The product distribution was also found to be influenced by the physical and chemical properties of the catalyst. Catalysts with strong acidity and smaller pores were observed to favor the formation of lighter hydrocarbons. In addition to the textural and acidic properties of the catalyst, the role of coke formation should not be neglected to ensure a comprehensive analysis of the catalytic performance.

Understanding the effect of reaction parameters on the production of levulinic acid from glucose

AbstractA significant and sustainable feedstock for many value added products is levulinic acid, which is basically a short‐chain fatty acid. The current study aims to comprehend how multiple factors affect the hydrothermal reactions that convert glucose to levulinic acid. Glucose can be readily obtained from lignocellulosic biomass and hence it is selected in the work as representative sustainable source. The effect of various operating parameters, including time (0–180 min), temperature (140–180°C), nitrogen pressure (0–25 bar), glucose concentration (3%–10%), agitation speed (100–300 RPM), and acid concentration (2%–6%); use of different salts (NaCl, AlCl3 6H2O, FeCl3); and different acids (HCl, H3PO4, H2SO4) on the reaction progress has been studied in a batch autoclave reactor. It was elucidated that pressure (only nitrogen purge was essential for reaction progress) or salt content changes did not affect sugar conversion significantly. The process was seriously influenced by the presence of acids, mostly in the form of homogeneous catalysts, and the most significant results were obtained for H2SO4. The highest levulinic acid yield (39.7 g/g) at 90 min, with nearly complete sugar conversion, was obtained under the ideal conditions of 160°C, 5% sugar loading, and 5% H2SO4 concentration. The current study indicates that the two primary operating parameters in this conversion process are temperature and time, with higher temperature and lower sugar concentration showing a rising tendency in sugar conversion. Overall, the study establishes a sustainable process for levulinic acid synthesis.

Process-controlled gas hydrate formation in coffee solutions for the application of cold concentration

CO2 gas hydrates occur in aqueous systems at elevated pressure and low temperature. They offer prospect to energy efficiency and gentle concentration of liquid foods. In current research, the formation of CO2 gas hydrates in a batch autoclave system for pure water and pure coffee (13–40 wt%) was investigated. Hydrate formation was highly reproducible. When reducing the temperature from 4 to 1 °C, induction times in 13 wt% coffee solutions approached zero, regardless of the applied target pressure (36 vs. 41 bar). Over the used range of temperature, pressure and concentration, different gas hydrate morphologies could be observed, ranging from dispersed gas hydrate crystals in coffee slurry to ordered, large-scale structures. The formation of large continuous hydrate structures bears application potential for efficient removal of gas hydrates from the concentrated liquid.

Batch to Continuous: From Laboratory Recycle Trickle Bed Test Reactor Data to Full-Scale Plant Preliminary Design—A Case Study Based on the Hydrogenation of Resorcinol

The fine chemical and pharmaceutical sectors are starting to advocate for the use of flow chemistry due to reasons such as the environment, health and safety, efficiency, cost saving, and regulatory compliance. The use of a trickle bed or fixed bed system could replace a batch autoclave typically used for hydrogenation reactions. However, there are few studies that detail the process from laboratory proof of concept through design to commercial realization. This study, using the production of 1,3-cyclohexanedione from the catalytic hydrogenation of resorcinol as a case study, demonstrates how the laboratory-scale recycle trickle bed can be used for catalyst screening and selection. Further, design data are generated by operation over a range of design superficial velocities and operating pressures that are used to derive a design correlation that is then used to specify a single stream plant at a level of definition consistent with a Preliminary Design for capital cost estimation. Finally, the further actions required in terms of data generation to increase the level of definition and confidence to a sanction grade or final design are discussed.

Catalytic Hydrodeoxygenation of Solar Energy Produced Bio-Oil in Supercritical Ethanol with Mo2C/CNF Catalysts: Effect of Mo Concentration

Transition metal carbides have emerged as an attractive alternative to conventional catalysts in hydrodeoxygenation (HDO) reactions due to surface reactivity, catalytic activity, and thermodynamic stability similar to those of noble metals. In this study, the impact of varying Mo concentration in carbon nanofiber-supported catalysts for the supercritical ethanol-assisted HDO of bio-oils in an autoclave batch reactor is discussed. Raw bio-oils derived from agave bagasse and corncob through solar hydrothermal liquefaction were treated at 350 °C. Our findings indicate that the presence of Mo has a strong impact on both product yield and chemical properties. Thus, a Mo concentration of 10 wt.% is enough to obtain high deoxygenation values (69–72%), resulting in a yield of upgraded bio-oil ranging between 49.9 and 60.4%, depending on the feedstock used, with an energy content of around 35 MJ/kg. A further increase in the Mo loadings (20 and 30 wt.%) reduced the loss of carbon due to gasification and improved the bio-oil yields up to 62.6 and 67.4%, without compromising the product quality.

Carbon Quantum Dots Coupled Au Nanoparticle as Fluorescence-Based DNA Biosensors for Dengue Virus Detection

This study introduces a novel DNA biosensor probe comprising carbon quantum dots (CQDs) derived from palm kernel shell biomass and gold nanoparticles (AuNPs) synthesized via the citrate reduction method. The CQDs were doped with ethylenediamine using a hydrothermal process employing a one-pot synthesis method in an autoclave batch reactor. The resulting CQDs exhibited exceptional photoluminescent (PL) properties, with an excitation wavelength of 360 nm and an emission wavelength of 430 nm. Transmission electron microscope (TEM) images showed the average particle sizes of the CQDs and AuNPs to be 2 nm and 15 nm, respectively. Carboxylic acid-modified CQDs were coupled to amine-modified ssDNA (PA) to construct the biosensor through the amine coupling technique. The AuNPs were modified through thiol coupling with Rhodamine B, L-cysteine, and thiol-modified ssDNA (PT). Both PA and PT probes were designed to complement the DEN-3 virus oligonucleotide. CQDs acted as fluorophores and energy donors in the biosensor, while the AuNPs functioned as nanoquenchers of fluorophores and energy acceptors. The resulting probe pair, CQDs-PA, and AuNPs-PT demonstrated remarkable Förster resonance energy transfer (FRET) and exhibited fluorescence turn-on upon titration with DEN-3. The biosensor displayed excellent sensitivity with a logarithmic calibration equation of 5.22LogC + 20.79 (R2 = 0.979), covering a linear range of 0.001 nM to 100 nM. The limit of detection (LOD) was determined to be 1.57 ± 0.71 nM. This innovative DNA biosensor, incorporating CQDs and AuNPs, holds promising potential for sensitive and specific detection of the DEN-3 virus.

Efficient Treatment of Antibiotic Cefalexin Sludge by Wet Oxidation: an Experimental and Theoretical Study

In the present study, wet oxidation of antibiotic cefalexin sludge from pharmaceutical wastewater treatment was investigated. The experiments were carried out in a stainless-steel batch autoclave reactor. The results show that the maximum removal rate of volatile suspended solids (VSS) can reach 91.3% at 260 °C within 60 min with an initial oxygen pressure of 1.0 MPa. Simultaneously, the chemical oxygen demand (COD) removal rate of 64.1% was reached. The antibiotic cefalexin was totally eliminated under wet oxidation conditions. DFT calculation was performed to illustrate the initial reaction pathway. The energy diagram proposed initial thermal hydrolysis pathway of cefalexin. These results indicated that wet oxidation provided a promising treatment method for the antibiotic cefalexin sludge, which can be used for the efficient removal of cefalexin.

Kraft cooking of birch wood chips: differences between the dissolved organic material in pore and bulk liquor

Abstract The delignification of birch chips during kraft pulping was investigated, targeting both the impregnation and cooking steps. Wood chips were impregnated using white liquor, white liquor + NaCl, water or NaCl aqueous solution. Then, the chips were cooked in batch autoclaves applying the same constant composition cooking conditions for all samples. Pulp and two fractions of black liquor (bulk liquor and centrifuged liquor representing the liquor inside the wood chips and fibers) were collected after different pulping times and analyzed for lignin and carbohydrate content. The dissolved wood components were precipitated from selected samples and characterized with respect to composition, molecular weight distribution and structural motifs. Cooking chemicals in the impregnation liquors led to faster delignification and xylan removal during cooking. Higher contents of lignin and xylan were measured in the lumen than in the bulk. The concentration profiles also showed accumulation of dissolved material in the lumen over time, suggesting significant mass transport limitation from lumen to bulk. Further analysis revealed higher fragmentation/degradation of dissolved material with increasing pulping time and in the bulk when compared to the lumen liquor, as demonstrated by the lower molecular weights and the changes in chemical shifts in the NMR spectra.

Enhanced Wet Oxidation of Excess Sludge from Pharmaceutical Wastewater Treatment by NaOH

In the present study, enhanced wet oxidation of excess sludge from pharmaceutical wastewater by NaOH as an alkaline homogeneous catalyst was investigated. The experiments were carried out in a stainless-steel batch autoclave reactor. The highest volatile suspended solids (VSS) removal rate, 95.2%, was achieved at 260 °C within 60 min with an initial oxygen pressure of 1.0 MPa and NaOH 0.5 g·L−1. Simultaneously, the chemical oxygen demand (COD) removal rate of 57.3% was reached. The increase in volatile fatty acids (VFAs) demonstrated that the degradation of sludge was greatly accelerated by NaOH. Interestingly, the production of acetic acid, an intermediate by-product generated from the oxidation of organic compounds, increased significantly. These results illustrated that NaOH is a promising catalyst for the utilization of wet oxidation liquid of excess sludge as a carbon source for the treatment of wastewater.

Optimization of Polypropylene Waste Recycling Products as Alternative Fuels through Non-Catalytic Thermal and Catalytic Hydrocracking Using Fresh and Spent Pt/Al2O3 and NiMo/Al2O3 Catalysts

In this work, the conversion of waste polypropylene to alternative fuels (liquid and gas) was performed through non-catalytic thermal and catalytic hydrocracking over NiMo/Al2O3 and Pt/Al2O3 catalysts. The process was carried out in an autoclave batch reactor at a temperature of 450 °C and a pressure of 20 bar, which were selected based on experimental optimization. The spent catalyst was also successfully regenerated at 700 °C under a hot airflow. Experiments were conducted to determine the optimum conditions to completely separate the deactivated catalyst from the solid residue easily. The regenerated catalyst was reused to facilitate the economic cost reduction of the process. The reactivated catalysts have almost the same catalytic properties as the fresh catalysts; this was confirmed by several characterization techniques, such as TGA, XRD, SEM, EDX, BET and FTIR. The produced liquids/gases were quantified and classified into their fractions by the number of carbon atoms and gasoline to diesel ratio using GC/MS. The viscosity, density, API gravity, pour point and flash point of oil cuts were also investigated to evaluate the quality of the resulting liquid from the reactions. The NiMo/Al2O3 catalyst gave the highest liquid hydrocarbons yield of 86 wt%, while the highest weight products of gasoline range hydrocarbon fractions of 49.85 wt% were found over the Pt/Al2O3 catalyst. Almost the same catalytic behavior was found with the regenerated catalysts compared to the fresh catalysts. However, the highest gaseous products at 20.8 wt% were found in the non-catalytic thermal products with an increase in the diesel fuel range of 80.83 wt%. The kinetic model was implemented using six lumps and fifteen reactions, and the apparent activation energies for the gasoline and diesel fractions were calculated. In general, all primary and secondary reactions show greater activation energy values on the Pt/Al2O3 catalyst than on the NiMo/Al2O3 catalyst.

Reactivity of Sulfur and Nitrogen Compounds of FCC Light Cycle Oil in Hydrotreating over CoMoS and NiMoS Catalysts

NiMoS and CoMoS catalysts were synthesized and applied to hydrotreating (HDT) of FCC light cycle oils (FCC-LCO) in an autoclave batch reactor at 613 K and 8.6 MPa H2. The S and N compounds in LCO were classified into four and three groups, respectively, in terms of the HDT reactivity. The individual and the competitive reactivities of the S and N compounds in the HDS and the HDN were investigated over the conventional CoMoS and NiMoS catalysts using S and N model compounds (dibenzothiophene, DBT, and carbazole, CBZ). In the HDS of DBT, both the direct desulfurization (DDS) and pre-hydrogenation pathway (HYD) were found to proceed, whereas the HYD pathway was favored for the HDN of CBZ. As a result, the NiMoS catalyst that facilitates the HYD pathway showed better activity in the HDN of LCO than the CoMoS (k = 10.20 × 10−2 vs. 1.80 × 10−2 h−1). Indeed, the HDS of LCO over the NiMoS was more favorable than that over the CoMoS catalyst (k = 4.3 × 10−1 vs. 3.6 × 10−1 h−1).

Solvothermal Liquefaction of Blackcurrant Pomace in the Water-Monohydroxy Alcohol Solvent System

Wet organic wastes are especially troublesome in valorization. Therefore, innovative solutions are still in demand to make valorization feasible. In this study, we tested a new transformation route of a blackcurrant pomace as a high-moisture industrial waste through a series of high-temperature and pressure solvothermal liquefaction experiments. The feedstock was directly converted under near-critical conditions of the binary solvent system (water/2-propanol). The goal was to examine the effect of conversion parameters (temperature, biomass-to-solvent ratio) on the change in the yield of resultant bioproducts, as well as the quality thereof. The experiments were conducted in a batch autoclave at a temperature between 250 and 300 °C. The main product of the transformation was liquid biocrude, which was obtained with the highest yield (ca. 52 wt.%) at 275 °C. The quality of biocrude was examined by ATR-FTIR, GC-MS, and elemental analysis. The ultimate biocrude was a viscous heterogeneous mixture containing various groups of components and exhibiting evident energy densification (ca. 145–153%) compared to the value of the feedstock. The proposed processing method is suitable for further development toward efficient valorization technology. More specifically, the co-solvent additive for liquefaction is beneficial not only for the enhancement of the yield of the desired product, i.e., biocrude, but also in terms of technological aspects (reduction of operational pressure and temperature).

Immobilization of Peroxo-Heteropoly Compound and Palladium on Hydroxyapatite for the Epoxidation of Propylene by Molecular Oxygen in Methanol.

Peroxo-heteropoly compound PO4[W(O)(O2)2] was synthesized on calcium-deficient hydroxyapatite using a reaction of surface [HPO4]2- groups on hydroxyapatite with a Na2[W2O3(O2)4] aqueous solution. The vibration of [HPO4]2- at 875 cm-1 became very weak, and the vibration of the peroxo-oxygen bond [O-O]2- at 845 cm-1 appeared in the FT-IR spectrum of the solid product, indicating that PO4[W(O)(O2)2] was formed on the surface of hydroxyapatite. The formed solid sample was further reacted with PdCl2(PhCN)2 in an acetone solution to fix PdCl2 between the O sites on the hydroxyapatite. Elemental analyses proved that the resultant solid contained 1.2 wt.% Pd, implying that PdCl2 molecules were immobilized on the surface of hydroxyapatite. The hydroxyapatite-based hybrid compound containing Pd and PO4[W(O)(O2)2] was used as a heterogeneous catalyst in a methanol solvent for propylene epoxidation by molecular oxygen in an autoclave batch reaction system. A propylene conversion of 53.4% and a selectivity for propylene oxide of 88.7% were obtained over the solid catalyst after reaction at 363 K for 8 h. The novel catalyst could be reused by a simple centrifugal separation, and the yield of propylene oxide did not decrease after the reaction for five runs. By prolonging the reaction time to 13 h, the highest yield of propylene oxide at 363 K over the solid catalyst was obtained as 53.8%, which was almost the same as that of the homogeneous catalyst containing PdCl2(PhCN)2 and [(C6H13)4N]2{HPO4[W(O)(O2)2]2} for the propylene epoxidation. Methanol was used as a solvent as well as a reducing agent in the propylene epoxidation by molecular oxygen. Small particles of Pd metal were formed on the surface of the hybrid solid catalyst during the reaction, and acted as active species to achieve the catalytic turnover of PO4[W(O)(O2)2] in the propylene epoxidation by molecular oxygen in methanol.

Polyurethane Recycling: Conversion of Carbamates-Catalysis, Side-Reactions and Mole Balance.

Diisocyanates, a key monomer in polyurethane, are generally lost during recycling. Polyurethane alcoholysis to carbamate and subsequent cracking to isocyanate represents a promising, phosgene-free recycling route. This work reports the thermal and catalytic cracking of a model carbamate (Methyl N-phenyl carbamate, MPC) to isocyanate (Phenyl isocyanate). Multiple catalysts (ZnO, Bi2O3, Al2O3, and Montmorillonite K-10) were evaluated in a closed system (batch autoclaves) to decompose MPC at temperatures of 160-200 °C, with a thorough analysis of the products and high (≥90%) mole balance. The thermal reaction was very limited at these temperatures, whereas the catalytic reaction led mainly to aniline and urea and seemed to be dominated by water adsorbed on the catalyst surface.

The role of Zn in the Cu-Zn-Al mixed oxide catalyst and its effect on glycerol hydrogenolysis

A series of Cu-Zn-Al oxide catalysts reduced in H2 was tested in glycerol hydrogenolysis in a stirred batch autoclave at 230°C. The catalysts were prepared by the precipitation – calcination method from layered double hydroxides (LDH) structures. The oxide forms of the catalysts were obtained by calcination of these structures at programmed temperatures, up to 350°C. The catalysts were characterized by the following methods: X-ray diffraction (XRD), temperature-programmed reduction (TPR), thermogravimetric analyses (TGA), N2-physisorption and temperature programmed desorption of ammonia (NH3-TPD). It was found that Zn plays acts as a structure modifier, influencing Cu dispersion and particle size. Consequently, Zn has an impact on the catalyst activity. In particular, the Zn effect had its maximum at the concentration corresponding to a ratio of Zn/(Cu+Al) = 0.35 where conversion of 65% and the selectivity to 1,2-propanediol of 70% was achieved after 60 min of reaction time.

Hydrogen and methane production from tomato processing plant waste by hydrothermal gasification

Hydrothermal gasification of tomato processing plant waste was examined in batch autoclaves at temperatures of 300–600 °C and pressures of 20.0–42.5 MPa. The catalytic effects of KOH and K2CO3 at the aforementioned temperatures and pressures were also investigated. While increasing the pressure enhanced methane yield, alkali addition improved both hydrogen and methane yields. The highest yields for H2 and CH4 were recorded as 27.4 and 21.8 moles kg−1 C at 600 °C and with KOH. In addition, carbon gasification efficiency (CGE) obtained was up to 86% while carbon liquefaction efficiency (CLE) was reduced to 3.5% with KOH at 600 °C and 20 MPa. A product gas with a calorific value of 24.9 MJ/Nm3 was obtained during hydrothermal gasification at 500 °C and 42.5 MPa, in the presence of KOH.

The effect of reaction time and temperature on the aquathermolysis process of heavy crude oil

Hydrothermal upgrading (HTU) performance during aquathermolysis process of heavy crude oil was conducted. All upgrading tests were conducted using a 300-ml autoclave batch reactor at 250 °C and 300°C under high pressure for 12, 24, 48, and 72 h in a nitrogen environment. Comprehensive analyses of physical and chemical characteristics of the upgraded oils, including viscosity, elemental composition, SARA fractions as well as Carbon number distribution in saturates of oil samples before and after upgrading, were studied to evaluate the hydrothermal upgrading performance. The results showed that, by increasing the reaction temperatures and times the upgrading performance was improved. The maximum upgrading performance was observed at 300 °C and 72 h for in terms of viscosity reduction, increasing the quantity and quality of saturates as a result of thermal decompositions of resin and asphaltenes, and increasing their quantity. In addition, an improvement in upgrading performance can be observed in the increasing of the H/C ratio, removing sulfur and nitrogen due to their desulfurization and denitrogenation. Generally, the obtained data showed that, HTU under studied conditions might be useful for heavy oil pretreatment due to the significant influence on viscosity reduction, heteroatoms removal as well as improving on its the main physical and chemical composition.