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• The synthesis of a number of alkyl esters via esterification reactions is studied. • An innovative split-reflux batch reactive distillation system (sr-BRD) is proposed. • Performance evaluation is made in terms of reaction conversion and product quality. • The sr-BRD operation can significantly improve conversion and product purity. The production of a number of methyl esters such as methyl decanoate (MeDC), methyl salicylate (MeSC), and methyl benzoate (MeBZ) by esterification reactions of several carboxylic acids such as decanoic acid (DeC), salicylic acid (ScA), and benzoic acid (BeZ) with methanol, respectively, through a reactive distillation system (batch or continuous) is cost-intensive and operationally challenging operation. It is difficult to keep the reaction species together in the reaction section due to wide boiling point differences between the reactants. Methanol (in those esterification processes) having the lowest boiling temperature in the reaction mixture can separate easily from carboxylic acid as the distillation progresses, resulting in a severe drop in the reaction conversion ratio of the acid employing batch/continuous distillation system. In order to overcome this type of challenge and to increase the overall reaction conversion, a novel split-reflux conventional batch reactive distillation configuration (sr-BRD) is proposed/studied in detail in this investigation. The optimal performance of BRD/ sr-BRD column is determined in terms of maximum achievable conversion of acids, and highest concentration of the esters produced for each chemical reaction scheme. The results for given separation tasks are compared with those obtained using conventional batch distillation (BRD) process. The optimization results clearly show that the sr-BRD process significantly improves the process efficiency, the conversion ratio of acid, and the product purity of methyl esters compared to that obtained via the BRD process. [ABSTRACT FROM AUTHOR]

The production of methyl decanoate (MeDC) through esterification of decanoic acid (DeC) with methanol by reactive distillation is operationally challenging and energy-intensive due to the complicated behaviour of the reaction system and the difficulty of retaining the reactants together in the reaction region. Methanol being the lightest component in the mixture can separate itself from the reactant DeC as the distillation proceeds which will cause a massive reduction in the conversion of DeC utilizing either a batch or continuous distillation process. Aiming to overcome this type of the potential problem, novel integrated divided-wall batch reactive distillation configuration (i-DWBD) with recycling from the distillate tank is established in this study and is examined in detail. This study has clearly demonstrated that the integrated divided-wall batch reactive distillation column (i-DWBD) is superior to the traditional conventional batch distillation (CBD) and both the divided-wall (DWBD), and split reflux divided-wall (sr-DWBD) batch reactive distillation configurations in terms of maximum achievable purity of MeDC and higher conversion of DeC into MeDC. In addition, significant batch time and energy savings are possible when the i-DWBD is operated in multi-reflux mode. [ABSTRACT FROM AUTHOR]

Abstract: Crude oil is an unrefined petroleum composed of wide range of hydrocarbon up to n‐C40+. However, there are also a percentage of light hydrocarbon components present in the mixture. Therefore, to avoid their flashing for safe storage and transportation, the live crude needs to be stabilized beforehand. This paper aims to find the suitable operating conditions to stabilize an incoming live crude feed to maximum true vapor pressure (TVPs) of 12 psia (82.7 kPa) at Terengganu Crude Oil Terminal, Malaysia. The simulation of the process has been conducted by using Aspen HYSYS. The obtained results illustrate that the simulation data are in good agreement with the plant data and in particular for the heavier hydrocarbons. For the lighter components, the simulation results overpredict the plant data, whereas for the heavier components, this trend is reversed. It was found that at the outlet temperature (85–90°C) of hot oil to crude heat exchanger (HX‐220X), the high‐pressure separator (V‐220 A/B) and the low‐pressure separator (V‐230 A/B) had operating pressures of (400–592 kPa) and (165–186 kPa), respectively, and the live crude was successfully stabilized to a TVP of less than 12 psia. The impact of main variables, that is, inlet feed properties, three‐phase separators operating pressure, and preheater train's performance on the product TVP, are also studied. Based on the scenarios analyzed, it can be concluded that the actual water volume (kbbl/day) has greater impact on the heat exchanger's duty; thus, incoming free water to Terengganu Crude Oil Terminal should be less than 19.5 kbbl/day (9.1 vol%) at the normal incoming crude oil flow rate of 195 (kbbl/day). [ABSTRACT FROM AUTHOR]

The synthesis of ethyl benzoate (EtBZ) via esterification of benzoic acid (BeZ) with ethanol in a reactive distillation is challenging due to complex thermodynamic behaviour of the chemical reaction and the difficulty of keeping the reactants together in the reaction zone (ethanol having the lowest boiling point can separate from the BeZ as the distillation proceeds) causing a significant decrease in the conversion of BeZ in a conventional reactive distillation column (batch or continuous). This might be the reason of not reporting the use of reactive distillation for EtBZ synthesis although the study of BeZ esterification reaction is available in the public literature. Our recently developed Integrated Conventional Batch Distillation (i-CBD) column offers the prospect of revisiting such reactions for the synthesis of EtBZ, which is the focus of this work. Clearly, i-CBD column outperforms the Conventional Batch Distillation (CBD) column in terms of product amount, purity and conversion of BeZ and eliminates the requirement of excess use of ethanol. For example, compared with CBD column, the i-CBD operation can yield EtBZ at a much higher purity (0.925 compared to 0.730) and can convert more benzoic acid (93.57% as opposed to only 74.38%). [ABSTRACT FROM AUTHOR]

Methyl decanoate (MeDC) is a fatty acid methyl ester (FAME) and is an important chemical compound with global production of 31 million tons per year. However, synthesis of methyl decanoate (MeDC) via esterification of decanoic acid (DeC) with methanol by reactive distillation is operationally challenging due to the difficulty of keeping the reactants together in the reaction zone; methanol being the lightest component in the mixture can separate itself easily from the other reactant deteriorating significantly the conversion of DeC using either a conventional batch or continuous distillation column. This is probably the main reason for not applying the conventional route to MeDC synthesis. Whether a semibatch distillation column (SBD) and the recently developed integrated conventional batch distillation column (i-CBD) offer the possibility of revisiting such chemical reactions for the synthesis of MeDC is the focus of this paper. The minimum energy consumption (Qtot) as the performance measure is used to evaluate the performances of each of these reactive column configurations for different ranges of methyl decanoate purity and the amount of product. It is observed that the use of i-CBD column provides much better performance than the SBD column in terms of the production time and the maximum energy savings when excess methanol is used in the feed. However, the SBD column is found to perform better than the i-CBD column when both reactants in the feed are in equal amounts. Also, the optimization results for a given separation task show that the performance of a two-reflux-interval strategy is superior to the single-reflux interval in terms of operating batch time, and energy usage rate in the SBD process at equimolar ratio. [ABSTRACT FROM AUTHOR]

Although batch reactive distillation process outperforms traditional reactor-distillation processes due to simultaneous reaction and separation of products for many reaction systems, synthesis of Methyl lactate (ML) through esterification of lactic acid (LA) with methanol in such process is very challenging due to difficulty of keeping the reactants together when one of the reactants (in this case methanol) has the lowest boiling point than the reaction products. To overcome this challenge, two novel reactive distillation column configurations are proposed in this work and are investigated in detail. These are: (1) integrated conventional batch distillation column (i-CBD) with recycled methanol and (2) integrated semi-batch and conventional batch distillation columns (i-SBD) with methanol recovery and recycle. Performances of each of these configurations are evaluated in terms of profitability for a defined separation task. In i-SBD column, an additional constraint is included to avoid overflow of the reboiler due to continuous feeding of methanol into the reboiler as the reboiler is initially charged to its maximum capacity. This study clearly indicates that both integrated column configurations outperform the traditional column configurations (batch or semi-batch) in terms of batch time, energy consumption, conversion of LA to ML, and the achievable profit. [ABSTRACT FROM AUTHOR]

Batch reactive distillation is well known for improved conversion and separation of desired reaction products. However, for a number of reactions, the distillation can separate the reactants depending on their boiling points of them and thus not only reduces the benefit of the reactive distillation but also offers operational challenges for keeping the reactants together. Methyl lactate (ML) synthesis via the esterification of lactic acid (LA) with methanol in a reactive distillation falls into this category and perhaps that is why this process has not been explored in the past. The boiling points of the reactants (LA, methanol) are about 490 K and 337 K while those of the products (ML, water) are 417 K and 373 K respectively. Clearly in a conventional reactive distillation (batch or continuous) methanol will be separated from the LA and will reduce the conversion of LA to ML significantly. Here, first the limitations of the use of conventional batch distillation column (CBD) for the synthesis of ML is investigated in detail and a semi-batch reactive distillation (SBD) configuration is studied in detail where LA is the limiting reactant and methanol is continuously fed in excess in the reboiler allowing the reactants to be together for a longer period. However, this poses an operational challenge that the column has to be carefully controlled to avoid overflow of the reboiler at any time of the operation. In this work, the performance of SBD for the synthesis of ML is evaluated using model based optimization in which operational constraints are embedded. The results clearly demonstrate the viability of the system for the synthesis of ML. [ABSTRACT FROM AUTHOR]

Catalysts play a vital role in petroleum and chemical reactions. Intensified concerns for cleaner air with strict environmental regulations on sulfur content in addition to meet economic requirements have generated significant interests for the development of more efficient and innovative oxidative catalysts recently. In this study, a novel homemade nano catalyst (manganese oxide (MnO2) over tin (IV) oxide (SnO2)) was used for the first time as an effective catalyst in removing dibenzothiophene (DBT) from kerosene fuel using hydrogen peroxide (H2O2) as oxidant in catalytic oxidative-extractive desulfurization process (OEDS). The catalyst was prepared by impregnation method with various amount of MnO2 loaded on SnO2. The oxidation step was carried out at different operating parameters such as reaction temperature and reaction time in batch reactor. The extractive desulfurization step was performed by using acetonitrile as solvent under several operating conditions (agitation speed and mixing time). The activity of MnO2/SnO2 catalyst in removing various sulfur compounds from kerosene fuel at the best operating conditions was investigated in this work. The results of the catalyst characterization proved that a high dispersion of MnO2 over the SnO2 was obtained. The experiments showed that the highest DBT and various sulfur compounds removal efficiency from kerosene fuel under the best operating conditions (oxidation: 5% MnO2/SnO2, reaction temperature of 75 °C, and reaction time of 100 min, extraction: acetonitrile, agitation speed of 900 rpm, and mixing time of 30 min) via the catalytic oxidative-extractive desulfurization process was 92.4 and 91.2%, respectively. Also, the MnO2/SnO2 catalyst activity was studied after six consecutive oxidation cycles at the best operating conditions, and the catalyst prove satisfactory stability in terms of sulfur compounds removal. After that, the spent catalyst were regenerated by utilizing different solvents (methanol, ethanol and iso-octane), and the experimental data explained that iso-octane achieved highest regeneration efficiency. [ABSTRACT FROM AUTHOR]

• Synthesis of methyl palmitate (MP) via reactive distillation was not studied in the past. • Conventional batch reactive operation (CBRD) is not appropriate for the purpose. • Semi-batch reactive distillation (SRBD) is a viable option for the synthesis of MP. • Performance of SRBD is evaluated against conversion, energy consumption and batch time. • 52–80% improvement in conversion of palmitic acid is obtained. Synthesis of methyl palmitate (MP) has not been considered in the past using a reactive distillation process (continuous or batch) due to the challenge of keeping the reactants palmitic acid (PA) and methanol (MeOH) together in the reactive zone. MeOH, being the lightest in the reaction mixture, travels up the distillation column as distillation proceeds and will be removed from the system via the distillate in a conventional batch reactive distillation (CBRD) column and thus will limit the conversion of PA. Therefore, in this work semi-batch reactive distillation (SBRD) column is proposed where additional methanol will be fed at the bottom of the column in a continuous mode allowing the chemical reaction to continue. However, as water (H 2 O) is one of the reaction products and is the second lightest component in the mixture, it will travel up the column next and will be removed in the distillate tank. Also due to wide difference in the boiling points of the reaction products and due to diminishing amount of water in the reboiler, the backward reaction will not be a dominating factor and therefore ignored in this work. With this backdrop, optimal performance of the SBRD column is evaluated in terms of conversion of PA to MP and energy consumption via minimization of the operating batch time for a wide range on MP purity. [ABSTRACT FROM AUTHOR]

• Synthesis of methyl decanoate (MeDC) by esterification reaction is considered using batch distillation. • Two batch distillation columns namely SBD and i-SBD are considered. • The performances of the columns is evaluated in terms of Total Annualised Cost. • i-SBD column offers cost saving of 36.61% compared to conventional batch column. The formation of methyl decanoate (MeDC) by esterification reaction of decanoic acid with methanol through batch/continuous reactive distillation columns is operationally challenging, energy intensive and thus cost intensive operation due to complex thermodynamic behaviour of the reaction scheme. Aiming to overcome the equilibrium restriction of the decanoic acid (DeC) esterification operation, to improve the process efficiency and to reduce the total annualised cost (TAC), the semi-batch distillation column (SBD) and the recently proposed integrated semi-batch distillation column configuration (i-SBD) are investigated here. The performances of each of these column operations are evaluated in terms of minimum TAC for a given separation task. In both column configurations, additional operating constraints are considered into the optimization problem to prevent flooding of still pot due to the continuous charging of methanol into it. This study shows the superiority of i-SBD mode of operation over SBD operation in terms of TAC. Also, the optimization results for a defined separation task indicate that the performance of multi-interval control policy is overwhelmingly superior to the single-interval control operation in terms of operating batch time, and overall annual cost in the i-SBD system providing about a time saving of 82.75%, and cost (TAC) saving of 36.61% for a MeDC (product) concentration of 0.945 molefraction. [ABSTRACT FROM AUTHOR]

The environmental impacts of waste cooking oil (WCO) can be profoundly serious when it is not handled properly. Instead of discarding leftover cooking oil as waste, recent technological advancements have made it possible to use WCO as a sustainable feedstock for biofuels production, while also addressing the disposal issue. This work developed an efficient and high stability hydrothermal WCO transformation process into green diesel fuel. In the present work, a homemade environmentally benign activated carbon was prepared from a bio-sourced precursor and impregnated with a Pd precursor. A set of experiments were conducted at 300 °C-350 °C, 40 and 50 bar, and times up to 240 min to evaluate the performance of Pd/AC catalysts against deoxygenation (DO) and deactivation reactions. The results showed a substantial enhancement of the activity and stability of the coated Pd/AC catalyst versus the uncoated one. Also, the green diesel fuel possesses an outstanding higher heating value of 46 kJ/mol. Based on experiments, the best kinetic model for the DO process was developed. The optimum kinetic parameters were obtained by the optimization approach. For a wide variety of operating conditions, the projected product conversion demonstrated satisfactory agreement with the experimental results, with absolute average errors of less than 8%. [ABSTRACT FROM AUTHOR]

The environmental impacts of waste cooking oil (WCO) can be profoundly serious when it is not handled properly. Instead of discarding leftover cooking oil as waste, recent technological advancements have made it possible to use WCO as a sustainable feedstock for biofuels production, while also addressing the disposal issue. This work developed an efficient and high stability hydrothermal WCO transformation process into green diesel fuel. In the present work, a homemade environmentally benign activated carbon was prepared from a bio-sourced precursor and impregnated with a Pd precursor. A set of experiments were conducted at 300 °C–350 °C, 40 and 50 bar, and times up to 240 min to evaluate the performance of Pd/AC catalysts against deoxygenation (DO) and deactivation reactions. The results showed a substantial enhancement of the activity and stability of the coated Pd/AC catalyst versus the uncoated one. Also, the green diesel fuel possesses an outstanding higher heating value of 46 kJ/mol. Based on experiments, the best kinetic model for the DO process was developed. The optimum kinetic parameters were obtained by the optimization approach. For a wide variety of operating conditions, the projected product conversion demonstrated satisfactory agreement with the experimental results, with absolute average errors of less than 8%. [ABSTRACT FROM AUTHOR]

In recent years, the use of abundant and low-cost biomaterials such as agricultural wastes in the preparation of activated carbon has been receiving a lot of attention. Besides, the conventional middle and heavy fuel cuts require a substantial and cost-effective sweetening process because sulfur in transportation fuel was found as one of the main causes of air pollution. The present work explored the preparation and characterization of microporous activated carbon (AC) catalysts prepared from olive stone by tubular furnace (Fe/AC1) and microwave (Fe/AC2) heating methods using H 3 PO 4 (85 wt%) as chemical activating agents. The kinetics of the oxidative desulfurization process (ODS) of a highly sour diesel fuel (sulfur content = 7361 ppm) was determined. The effect of the heating method on the texture and morphological structure, surface area, and surface chemistry of the carbons produced was investigated. Fe/AC1 was prepared in a horizontal tabular furnace at 650 °C calcination temperature and 90 min residence time under a nitrogen atmosphere, while Fe/AC2 was performed in a microwave reactor with 565 W and 7 min microwave power and irradiation time respectively. The catalysts were characterized by N 2 - adsorption-desorption, SEM-EDX, FTIR, XRD, XRF, TGA, PSD, and elemental analysis. It was found that the use of a tubular furnace for heating the olive seeds resulted in a higher surface area and yield. Also, the characterizations of the Fe/AC1 catalyst showed that it has a large surface area of 1175 m2/g and micropore volume of 0.6954 cm3/g whereas Fe/AC2 had a surface area of 854 m2/g and micropore volume of 0.6936 cm3/g. Moreover, SEM-EDX results indicated that Fe/AC1 was dispersed uniformly better than Fe/AC2. Also, TGA/DTA results revealed better results for Fe/AC1 than Fe/AC2 making it favorable in ODS experiments. The difference in texture and chemical properties is caused by the heating methods. The desulfurization removal was investigated under different temperatures (80, 90, 100, 110 °C) and reaction time (30–90 min). The kinetics of the ODS were conducted over the efficient Fe/AC1 catalyst prepared. It was shown that the ODS reaction followed pseudo-first-order kinetics with a fairly low activation energy over the catalyst was 40.71 kJ/mol. [Display omitted] [ABSTRACT FROM AUTHOR]

The deactivation of the oxidative desulfurization (ODS) catalysts is a challenge and is a major concern in industrial catalytic processes. In this work, an activated carbon (AC) was prepared from agricultural waste and modified to withstand the ODS activity loss over time. The AC was impregnated with manganese and coated with aluminum oxide to prolong the activity lifetime. The catalysts were characterized by nitrogen adsorption-desorption, scanning electron microscope, energy dispersive X-ray, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and transition electron microscope (TEM). The BET surface areas of the examined AC materials were 814.48 m2/g, 784.76 m2/g, and 755.03 m2/g for the AC, Mn/AC, and coated Mn/AC catalysts, respectively with a dominance of microporous pore size. The TGA showed that the coating layer retards the degradation of the active metal and suppresses phase transitions. XRD showed no change in the structure of the catalyst with a coating layer, and from the TEM analysis, the coating layer thickness was 3.6 nm. The kinetics of the ODS catalysts were investigated. It was shown that the ODS reaction follows the first-order kinetics and is not influenced by the coating layer. The activity decay was also investigated. It is found that the activation energy of the deactivation reaction over the coated catalyst was higher than the uncoated catalyst. [Display omitted] • High-stability catalysts from agricultural waste with by sol-gel technique • Highly active carbon-based catalyst for oxidative desulfurization of fuel • The deactivation reaction rate was hindered by coating of the catalyst. • The coating does not affect the kinetics of ODS reaction. [ABSTRACT FROM AUTHOR]

• Highly active Pd/AC catalysts from agro-waste for deoxygenation of waste cooking oil. • Microporous structure with acidic sites to enhance deoxygenation. • Protective coating layer alters the deactivation reaction of the deoxygenation catalyst. • The coating layer did not influence the kinetics of deoxygenation reaction. Nowadays, one of the most challenging problems in the production of green diesel fuel from fats sources is the deactivation of the deoxygenation catalyst after a certain period of time. The structure of the catalyst is damaged due to several problems and the performance is degrading over time. In this work, a high stability deoxygenation catalyst was prepared from agricultural waste and used for hydrothermal production of green diesel fuel from waste cooking oil. The support of the catalyst was prepared using apricot seeds. Palladium (Pd) was loaded by the incipient wetness impregnation method. The Pd/AC substrate was coated by a nanofilm aluminum protective layer using the sol–gel method to prevent rapid deactivation of the catalyst, prolong the catalyst lifetime and enhance the stability. The characterization tests showed good thermal stability, a uniform coating around the Pd/AC substrate, and a high surface area of 726.9 m2/g of the coated catalyst. Micropores increase the activity of oleic acid deoxygenation from attributed to improved acid site accessibility within the fluffy Pd/AC substrate. Kinetic experiments were carried out in a hydrothermal autoclave reactor under an inert atmosphere (N 2) over the coated and the uncoated catalyst at a temperature range of 300–350 °C, pressure range 30–50 bar and residence time up to 3 h. The results showed that the catalytic deoxygenation of the oleic acid is a first-order reaction. The rate of deactivation of Pd/AC deoxygenation catalyst was determined at 350 °C and 50 bar in a hydrothermal autoclave reactor. The results showed that deactivation reaction of the Pd/AC catalysts followed first-order kinetics and occurred by the poisoning mechanism. The deactivation reaction was significantly altered due to coating of deoxygenation catalyst and elevating of the activation energy of the deactivation reaction. [ABSTRACT FROM AUTHOR]