Extractive Desulfurization Research Articles

Choline-based Deep Eutectic Solvent for Extractive Oxidative Desulfurization of Model Oil

One of the hardest processes encountered by petroleum refining is sulfur elimination from fuel oil. There are many traditional methods executed but they caused drawbacks such as poor selectivity of sulfur compounds and toxic raw materials. Extractive oxidative desulfurization (EODS) caught the interest of researchers due to high selectivity of sulfur compounds and great desulfurization. Currently, researchers are investigating the use of ionic liquids (ILs) as green extractant, unfortunately they are expensive. This research is proposing and comparing the use of cheap biodegradable solvents called deep eutectic solvents (DESs), as extractants in removing sulfur from fuel oil. The DESs are synthesized through a combination of choline chloride - orcinol and choline chloride - ethylene glycol, and their structure is confirmed through FTIR. Their thermal properties are characterized by DSC and TGA. Their desulfurization performance is evaluated by type of DESs, different ratios of DES and model oil, different ratios of oxidant and sulfone and various temperatures which these factors are found to influence the result. The optimum conditions are found to be at 1:1 for DES and model oil ratio, 4 for O/S ratio and temperature at 85 °C with the extraction efficiency of 99.98%. In conclusion, this DES has high potential to be the cheap green alternative to the conventional extractant for extractive oxidative desulfurization process.

Evaluation of Conventional Polar Solvents for Extractive Desulfurization of Model Diesel Fuels

Evaluation of Conventional Polar Solvents for Extractive Desulfurization of Model Diesel Fuels

APPLICATION EXTRACTIVE DESULFURIZATION USING PIPERIDINIUM BASED IONIC SALT WITH FeCl3 AS LEWIS ACID

The study involves the synthesis of inorganic salts by reacting the organic salts with ferric chloride and organic salts (1) [mAMPi]Br, (2) [pAMPi]Br derived from the nitrogenous base of Piperidinium. Spectroscopic and physical techniques were used to characterize the prepared compounds, including mass spectrometry, infrared FT-IR, micro-elemental analysis, and 1H-NMR nuclear magnetic resonance spectroscopy. The extractive desulfurization method was used in this study, and the produced compounds were examined using model oil that contained 1000 ppm of the sulfur compound. Dibenzothiophene (DBT) was dissolved in an n-hexane solvent, and ultraviolet (UV) was used as a quantitative analysis method to calculate the percentages of sulfur removal. Future research may be able to enhance the sulfur removal rate provided by the prepared compounds, which were showed an acceptable result

Improvement of extractive desulfurization for Iraqi refinery atmospheric residual

Extractive desulfurization (EDS) process of petroleum fuels via effective solvents has been widely investigated in recent decades and has an excellent future as an alternative technique to HDS process. This study was focused on removal of sulfur compounds from heavy Iraqi atmospheric residual oil (IARO) via EDS process without affecting its other properties. Different hydrocarbon solvents (light naphtha, n-heptane and n-hexane), solvent to oil ratios (4/1, 8/1, and 12/1), extraction times (30, 60, and 120 min), and extraction temperatures (30 °C, 60 °C and 90 °C) were investigated on the precipitation of sulfur in Iraqi atmospheric oil residue. The results were showed that increasing of solvent to oil ratio, extraction times, and extraction temperatures enhanced the performance of EDS process. The experimental results proved that 96% of sulfur compounds were eliminated from heavy residual oil using effective n-hexane as solvent under moderate operating conditions as follow: extraction temperature of 90 °C, extraction time of 60 min, and solvent to oil ratio of 12/1. This study prove that extractive desulfurization via hexane-like solvents at the best experimental conditions can achieve satisfactory sulfur removal efficiency of heavy oil via safe, fast, economically and effective process.

Boosting oxidative desulfurization from liquid fuels with CuO-MgO assisted by MgMoO4 co-catalyst

Developing a highly efficient catalyst is one of the important topics in the field of oxidative desulfurization from liquid fuels. In this study, the composite metal oxide catalysts (CuO-MgO) with co-catalyst MgMoO4 were prepared by co-precipitation method with simple process, high efficiency and good performance and their structures characterized. An efficient extractive catalytic oxidative desulfurization (ECODS) system for liquid fuel was successfully developed on the basis of as-prepared CuO-MgO-MgMoO4 (CuMgMo) as the catalyst, sodium hypochlorite (NaClO) as the oxidant, and acetonitrile as the extractant. Taking the n-decane and n-tetradecane containing dibenzothiophene (DBT) as the test model oil sample, the main parameters influencing desulfurization performance were examined in detail, such as the molybdenum content, the dosage of CuMgMo, the reaction temperature, the initial S-concentration, the different extractants, the volume ratio of extractant to oil, the different oxidants, and the molar ratio of NaClO to DBT. Based on optimized desulfurization reaction conditions, the model oil containing different sulfur compounds (benzothiophene, 4-methyldibenzothiophene, and 4,6-dimethyldibenzothiophene) and the real oil (straight-run gasoline, straight-run kerosene, and straight-run diesel) were further tested. Based on the free radical trapping experiments and the calculation of density functional theory, the reaction mechanism was deeply explored. The results showed that the de-electron reaction of DBT was mainly catalyzed by MgMoO4 and the reaction of HClO obtaining electron was mainly catalyzed by CuO. MgMoO4 plays an assisting role in improving the catalytic reaction rate. This work will provide a useful reference for the construction of efficient ECODS system using composite metal oxides.

Designing Inorganic–Organic Dual-Acid Deep Eutectic Solvents for Synergistically Enhanced Extractive and Oxidative Desulfurization

Designing Inorganic–Organic Dual-Acid Deep Eutectic Solvents for Synergistically Enhanced Extractive and Oxidative Desulfurization

Diesel Desulfurization Experiments in Microchannels with PEG 300: An Understanding of Extractive Deep Desulfurization

Diesel Desulfurization Experiments in Microchannels with PEG 300: An Understanding of Extractive Deep Desulfurization

Peroxo-polyoxometalate encapsulated within zirconium-based metal organic frameworks for extractive and oxidative desulfurization of fuels

The combustion of a large amount of sulfur-containing liquid fuel has caused a series of environmental pollution problems, so the desulfurization of fuel oil is a very important and meaningful research work. Based on the high-activity catalyst, extractive oxidation desulfurization technology can efficiently and gently remove the organic sulfides in fuel. Heterogeneous catalysts encapsulating peroxophosphotungstate (TBA)3PW4 in the pores of zirconium-based MOFs (UiO-66 and UiO-67) were prepared for desulfurization of multicomponent simulated fuel combining extraction and oxidation. Reaction conditions, desulfurization efficiency of different materials and activity of different sulfides were optimized and analyzed. The results show that (TBA)3PW4@UiO-67 shows high catalytic activity due to its large window size, and has good reusability and structural stability.

Molecular modeling of 1-butyl-3-methylimidazolium based ionic liquids for potential applications in the desulfurization of diesel fuel

The sulfur compounds in diesel fuel produce harmful environmental pollutants during combustion. Hydrodesulfurization (HDS) is the most common technique to reduce the sulfur content of diesel fuel but cannot effectively remove aromatic sulfur compounds to produce ultra-low-sulfur diesel. Ionic liquids (ILs) show potential as alternative solvents for extractive desulfurization to be implemented after a conventional HDS process, but the mechanism is not well understood. This work focuses on using a combination of molecular simulation free energy calculations and detailed structural analysis to better understand the molecular-level interactions between dibenzothiophene and seven common imidazolium-based ILs. The free energy calculations suggest that the ILs interact differently with thiophene and dibenzothiophene. No specific interactions were observed between the anion and dibenzothiophene; varying the anion showed no remarkable differences in the observed interactions. It was determined that interactions between dibenzothiophene and the cation were more significant; π-π stacking between the imidazole ring and thiophene ring plus favorable electrostatic interactions between the alkyl chain and benzene rings were observed. The primary goal of this work is to use molecular simulations to complement current experimental research to identify suitable ILs for potential extractive desulfurization applications.

Molecular mechanism and experimental study of fuel oil extractive desulfurization technology based on ionic liquid

In recent years, the sulfur-containing substances produced by fossil fuel combustion have caused overwhelming pollution to the ecological environment, and fuel desulfurization research is imperative. In this paper, 16 ionic liquids (ILs), which are environmentally friendly, easily degradable and have good prospects for industrial application, were selected by combining four cations and four anions for fuel desulfurization research. The desulfurization mechanism of ILs was first investigated by molecular mechanism studies, in which quantum chemical simulations were used for preliminary screening based on the selectivity coefficient of infinite dilution activity coefficient. And the experimental study of extraction desulfurization was carried out with dibenzothiophene (DBT) and n-heptane as model oils. The above mechanism study and experiments examined the effects of temperature, initial fuel oil concentration and ILs to fuel oil feed ratio on the extraction efficiency, and the results showed that both [C2COOCH3ImC6H13][N(CN)2] and [C2COOCH3ImC6H13][NTF2] ILs have more prominent extraction properties. Among them, [C2COOCH3ImC6H13][NTF2] exhibits high desulfurization efficiency for a wide range of sulfur concentration in fuel oils at room temperature due to the advantages of simple preparation method and easier industrialization of the [C2COOCH3ImC6H13][NTF2]. The above experimental results are fully consistent with the molecular simulation predictions, indicating that the theoretical study and experimental method proposed in this paper are simple and feasible.

Preparation of porous hollow spherical MoOX/C catalyst for efficient extraction and oxidative desulfurization

Preparation of porous hollow spherical MoOX/C catalyst for efficient extraction and oxidative desulfurization

Ionic liquids based on metal halide complex salts and their applications in extractive desulfurization of liquid fuel: A review

In this review, different types of sulfur compounds (thiols, sulfides, benzothiophenes, etc.) present in liquid fuel can be conveted by combustion to sulphur dioxide, which is a prevailing source of environmental pollution, so many countries proposed standard S-content to lower than 10 ppm. Although, hydrocracking process produce low-sulfur content, but still needs more desulfurization, researches have done using many technologies, among that were: A: Adsorptive desulfurization (ADS), through adsorptive over such surfaces. B: Oxidative Desulfurization (ODS), using an oxidant agent to convert sulfure into form can be removed. C: Hydrodesulfurization process (HDS), which is most efficient than other methods to remove organo sulfur (aliphatic and aromatic). D: Bio desulfurization (BDS), employed microorganisms to remove sulfur atom from organic S-compounds and can be environmental friendly. E: Extractive desulfurization (EDS), is a prosses using solvent as liquid- liquid extraction. The above technologies faced some disadvenges such as nature of volatile molecular solvent coupled with limitation of loss solvent, difficult of extraction regeneration, environmental pollution and costly, as required industrial unit operation at high temperature and pressure beside the expensive of hydrogen gas and catalysts. Therefore, it has been a challenge research investigation to explore a new deep extractive desulfurization methods. Among these treatments was using ionic liquids (ILS) which composed of heterocyclic organic cation (imidazolium, pyridinium, etc.) and different inorganic anions my be applied to decrease temperature, non-toxic, chemical stability, environmental friendly as green solvent, so, (ILS) used for many applications and deep eutectic desulfurization among that. Recently, studies showed that metal contains ionic liquids for extractive sulphur removal have a high influence and ability for sulphur removal than metal free (ILS) , which may be a good solvent in separation and removal of aromatic sulphur from fuel. The Fe, Co, Ni, Zn, Cu, etc. metals halides were used with organic cation to form complexes salts. The mechanism was investigated that the metal (ILS) have almost good extraction ability explained by the complexation of metal moiety with sulfur compounds.

Probing molecular interactions in mixed system of green solvent ethyl lactate with oligomers of polyethylene glycol

Polyethylene glycol and its oligomers are potential hydrogen bond donors that act as a green, effective, non-toxic, non-corrosive and recyclable molecular component for extractive desulfurization of liquid fuels and variety of other applications. The aim of this investigation is to explore the molecular interactions via variations in viscosity that occur on mixing these glycols with green solvent ethyl lactate. Dynamic viscosities (η) for pure solvents and binary mixtures of ethyl lactate and glycols oligomers (mono/di/tri/tetra-ethylene glycol) were measured at varying temperatures T/(K) = (298.15–313.15; with an interval of 5). Viscosity deviations (Δη) along with excess thermodynamic parameters of activation for viscous flow as Gibbs free energy (ΔG∗E), Enthalpy (ΔH∗E) and Entropy (ΔS∗E) were derived from experimental data. The Δη and ΔG∗E values were further correlated using Redlich-Kister polynomial expression. The experimentally obtained viscosity values were compared with 10 generalised literature models (Arrhenius, Kendall, Kendall-Monroe, Grunberg-Nissan, Hind, Katti-Chaudhri, Heric, McAllister three-body, McAllister four-body and Jouyban-Acree models). The average standard deviation percentages (ASD %) were calculated for all the models to compare the quality of correlation with experimental data. The minimal ASD % for McAllister four-body and Jouyban-Acree models in the working systems indicate that the multiparameter relations have the best capability of reproducing the experimental values. The temperature induced variations were also discussed together with molecular interactions. Further, quantum mechanical density-functional theory and graph theoretical approaches were used to explore the extent of interactions among the components.

Extractive Desulfurization in Microchannel Contactors Using Deep Eutectic Solvents: Optimization Using Central Composite Design (CCD) and Flow Pattern Mapping

Extractive Desulfurization in Microchannel Contactors Using Deep Eutectic Solvents: Optimization Using Central Composite Design (CCD) and Flow Pattern Mapping

Desulfurization of Diesel Using Ionic Liquids: Process Design and Optimization Using COSMO-Based Models and Aspen Plus.

Sulfur dioxide emissions from fossil fuel combustion have been known to cause detrimental health and environmental effects. The currently used hydrodesulfurization (HDS) method employed by refineries has several drawbacks, such as excessive hydrogen consumption, high energy demand, and inability to remove complex organosulfur compounds, which have limited its ability to produce ultralow sulfur diesel (ULSD) at reasonable operating and capital costs. Ionic liquids (ILs) have been widely studied for their potential to replace conventional HDS. However, while their success has been demonstrated at the laboratory level, studies on industrial-scale feasibility and their integration into process simulators such as Aspen Plus are limited. In this work, 26 commercially available ILs have been screened using COSMO-based models and Aspen Plus for the desulfurization of diesel fuel and several possible process configurations have been examined. In particular, the challenge of ionic liquid regeneration, which has largely been ignored in the literature, has also been addressed and several potential regeneration methods have been proposed including extractive regeneration (E-RE) and stripping regeneration using nitrogen and air as stripping media (S-RE). The results indicate that, among the 26 ILs studied, 1-butyl-3-methylimidazolium thiocyanate is the most promising as a solvent for extractive desulfurization (EDS), E-RE, and S-RE. E-RE was found to be more effective for the removal of dibenzothiophene (DBT), while S-RE is more suited to the removal of thiophene and benzothiophene (BT). As a result, an optimized diesel desulfurization process using 1-butyl-3-methylimidazolium thiocyanate has been proposed that achieves ULSD with <10 ppm total sulfur in simulation studies, with complete recycling of the IL and minimal loss of the model diesel.

Uncovering the Critical Factors that Enable Extractive Desulfurization of Fuels in Ionic Liquids and Deep Eutectic Solvents from Simulations.

Environmental regulatory agencies have implemented stringent restrictions on the permissible levels of sulfur compounds in fuel to reduce harmful emissions and improve air quality. Problematically, traditional desulfurization methods have shown low effectiveness in the removal of refractory sulfur compounds, e.g., thiophene (TS), dibenzothiophene (DBT), and 4-methyldibenzothiophene (MDBT). In this work, molecular dynamics (MD) simulations and free energy perturbation (FEP) have been applied to investigate the use of ionic liquids (ILs) and deep eutectic solvents (DESs) as efficient TS/DBT/MDBT extractants. For the IL simulations, the selected cation was 1-butyl-3-methylimidazolium [BMIM] and the anions included chloride [Cl], thiocyanate [SCN], tetrafluoroborate [BF4], hexafluorophosphate [PF6], and bis(trifluoromethylsulfonyl)amide [NTf2]. The DESs were composed of choline chloride with ethylene glycol (CCEtg) or with glycerol (CCGly). Calculation of excess chemical potentials predicted the ILs to be more promising extractants with energies lower by 1-3 kcal/mol compared to DESs. Increasing IL anion size was positively correlated to enhanced solvation of S-compounds, which was influenced by energetically dominant solute-anion interactions and favorable solute-[BMIM] π-π stacking. For the DESs, the solvent components offered a range of synergistic, yet comparatively weaker, electrostatic interactions that included hydrogen bonding and cation-π interactions. An in-depth analysis of the structure of IL and DES systems is presented, along with a discussion of the critical factors behind experimental trends of S-compound extraction efficiency.

Stable hydrogen bonding interactions in supramolecular deep eutectic solvents based on carbon quantum dots: For extraction and oxidative desulfurization

Supramolecular deep eutectic solvent (SUPRADES) was a promising green solvent with physicochemical properties that was similar to those of conventional deep eutectic solvent (DES). The supramolecular deep eutectic solvent-based nanofluidic system (β-CD-CA/CQDs) was constructed by using β-cyclodextrin as the hydrogen bond acceptor and citric acid as the hydrogen bond donor with the addition of carbon quantum dots (CQDs). The addition of CQDs enhanced the desulfurization ability and hydrogen bonding stability of SUPRADES. By controlling the content of CQDs solution, the viscosity of β-CD-CA/CQDs can be easily changed without altering its eutectic nature. The effects of temperature, O/S, sulfur content, oil content and different sulfides on the sulfur removal of β-CD-CA/CQDs were investigated. The sulfur removal of β-CD-CA/CQDs was up to 99.32% at 50 °C. The cyclic voltammetric tests, recovery experiments, and characterization all showed that β-CD-CA/CQDs had excellent recoverability and stability in desulfurization.

Synergetic ultrasound assisted catalytic oxidative extractive desulfurization of tire pyrolysis oil employing sustainable protic deep eutectic solvents

One-pot ultrasound-assisted selective oxidative extractive desulfurization (UA-SOEDS) of tire pyrolysis oil (TPO) was carried out with sustainable protic deep eutectic solvent (pDES) synthesized with quaternary ammonium salts as HBA and organic acids as HBD. The Tetrabutyl ammonium chloride and malic acid-based pDES with moderate viscosity resulted in a maximum Sulphur removal of (92.6 % (w/v)). A central composite design-based optimization of essential variables (US time (12 min), US temperature (333.15 K), US power (1.2 kW) and pDES/TPO ratio (22.5 % v/v)) was carried out resulting in an effective sulfur removal rate of (93.6% w/w). The pDES post extraction was recovered with the addition of isooctane and reused for consecutive cycles of UA-SOEDS process, loosing its characteristic oxidative extraction property after 3rd cycle (68.53%). The chromatographic analysis confirmed the presence of long-chain hydrocarbons in the oxidized TPO which confirms its property as a good fuel. The physicochemical properties and the calorific value of the resulting base oil were determined making it a suitable candidate as an alternative green fuel meeting the international standards of soluble Sulphur.

Intensification of extractive desulfurization in micro-channels using triethylamine/propionic acid as deep eutectic solvent

In this study, the extractive desulfurization from the model fuel was investigated in different micro-channels using triethylamine/propionic acid with the molar ratio of 1 to 3 ([TEA:3Pr]) as DES. In this regard, the effect of operating parameters (i.e., extraction time, temperature, and fuel to DES volume ratio) and micro-channel geometrical parameters (i.e., the diameter of the micro-channel, and length of the micro-channel) on the sulfur removal and volumetric mass transfer coefficient was investigated. Moreover, the effect multiple extractive desulfurization cycles, regeneration of spent [TEA:3Pr] has been also investigated. It was found that the best geometry for the micro-channel is 0.6 mm in the diameter and 20 cm in length considering the sulfur removal and mass transfer. The slug and throat-annular flow regimes were observed in the different micro-channels through two-phase flow visualization. The achieved sulfur removal was 70.8%, 68.7%, and 44.4% from the model fuels containing dibenzothiophene (DBT), benzothiophene (BT), and thiophene (Th) in a very short residence time of 17 s, respectively. The overall volumetric mass transfer coefficient in the micro-channel was 0.679 s−1 in the fuel to DES volume ratio of 5. It was also found that deep sulfur removal can be achieved using multiple-extraction cycles.

Extractive desulfurization of liquid hydrocarbon fuel using ionic liquids: Cationic and anionic selection through Principal Component Analysis and experimental study

Extractive desulfurization using ionic liquids has gained more attraction due to simplicity and easy operating conditions of sulfur compounds removal from liquid hydrocarbon fuels. But the selection of proper cations and anions are still the most challenging parts of all researches. In the present study, a new methodology was developed for screening of cation and anion molecules to obtain maximum sulfur removal efficiency. At first, the best structural descriptors were selected using Genetic algorithm. The different kinds of 1D, 2D and 3D molecular descriptors for a diverse library of cation/anion have been evaluated, including 114 cations and 48 anions. Then, the most proper cations and anions have been selected using Principal Component Analysis (PCA) after evaluating the most accurate structural descriptors for various cations and anions. It was concluded that ionic liquids (ILs) comprise imidazolium and pyridinium cations with hexyl chain, combined with the [N(CN)2] and [Ac] anions, are promising ILs as extraction solvents for extractive desulfurization. To evaluate the obtained results, one of the selected ILs, 1-Hexyl-3-methyl pyridinium dicyanamide ([HMPY][N(CN)2]), has been examined and has been synthesized for the first time as extractant for EDS. The synthesized IL was examined through NMR and FTIR analysis. After that by investigating results and the slope of tie-lines, distribution coefficient, selectivity and the capability of selected IL to sulfur removal of DBT or BT in both phases, it is observed that [HMPY][N(CN)2] is a proper solvent for extraction of DBT or BT from n-heptane.