Experimental Study on Catalytic Hydroprocessing of Solubilized

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Experimental Study on Catalytic Hydroprocessing of Solubilized Asphaltene in Water: A Proof of Concept to Upgrade Asphaltene in Aqueous Phase Parsa Haghighat, Lante A Carbognani Ortega, and Pedro Rafael Pereira-Almao Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.6b00275 • Publication Date (Web): 22 Mar 2016 Downloaded from http://pubs.acs.org on March 23, 2016

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consisted of two cyclohexyl fused hydrocarbons with higher selectivity to naphthenic and lower selectivity to aromatic compounds. Detecting CO2 as a major component in the gas phase in parallel with the results of GC/MS before and after hydroprocessing confirms that oxygen removal is dominated by decarboxylation. Keywords: oxidation, hydroprocessing, solubilized asphaltene in water, aqueous phase reaction. Introduction Despite all the practices in refineries for optimization and development of efficient and environmental friendly technologies, asphaltene processing remains a challenging unsolved problem. The common thermal cracking of asphaltene known as delayed coking which is widely implemented in refineries and upgraders is a severely inefficient process due to high rate of coke formation and low quality of distillates. Although catalytic processes such as H-oil and LC-fining were commercialized for upgrading of heavy oil such as vacuum residue and pure bitumen, they never successfully applied to pure asphaltene fractions because of high catalyst deactivation rate and coke formation. In the early years of the twenty first century, asphaltene gasification was implemented for the first time by Opti-Nexen in Alberta, Canada to apply syngas product to generate steam for SAGD applications and at the same time to produce hydrogen for hydrocracking units.1 However, these attempts could not convince industry to consider gasification as a reliable alternative technology for asphaltene conversion, specifically due to significant decline of natural gas price after 20082 mainly by the increased production of shale gas. Asphaltene is defined

based on solubility precipitating in light alkanes such as hexane or heptane and being soluble in aromatic compounds such as toluene. Although asphaltenes are typically considered as the heaviest and most polar fraction of crude oil3, they can be found within a very wide range of molecular weight spanning from about 500-2000 amu.4,5 The high molecular weight assumption of asphaltene is mostly due to the self-association tendency of these molecules under modified solubility conditions or when they are concentered in the oil residual fractions inducing their 2 ACS Paragon Plus Environment

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separation from the media.6,7 Decades of unprosperous exercises on conventional carbon rejection or hydrogen addition methods showed that new chemistry pathways are required to cope with asphaltene processing challenges.

Heading towards finding innovative technologies for heavy oil processing, upgrading of crude residua and biomasses in water at near critical point (374◦C, 22.1 MPa) was extensity discussed in several articles.8-14 At high temperatures close to critical point, properties of water such as density, viscosity, dielectric constant and ion product changes drastically. By increasing the temperature, dielectric constant and density of water decreases which causes higher solubility of heavy hydrocarbons in the water medium. At the same time the ion product of water changes by increasing the temperature (maximized at 300oC) which means more water dissociation and reactivity in this reaction medium.9,15,16 All these properties make water at elevated temperatures a favorable solvent medium for reaction of hydrocarbons. Water is the side product of biocrude liquefaction and pyrolysis. Therefore, further processing of biocrude products are usually carried out in aqueous medium. In several studies, catalytic and non-catalytic aqueous hydrogenation of lignin, the wood-based biomass with natural polymeric structure were explored.17 Lignin is an appropriate representative component for solubilized oxygenated asphaltene in water due to its large molecular weight, complex structure and high oxygen/carbon ratio. Patil et al. showed that hot compressed water below supercritical condition presented promotional effects on lignin conversion while bases such as NaOH increase the solubility of lignin during hydrogenation. They detected phenols, guaiacols and syringols as the main liquid products of reaction.12 Mu et al. examined four different noble metals over activated carbon for hydroprocessing of lignin in water at 250°C and hydrogen pressure of 4 MPa. In the presence of Pd, Pt or Rh, catechol was produced after reaction which was the reason for coke formation and decline of the catalyst active sites. However, the full hydrogenation without catechol production was obtained with Ru 3 ACS Paragon Plus Environment

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catalyst while cyclohexanol and 4-methyl-cyclohexanol were found as main products18. Singh et al. studied the effect of solvent on depolymerisation and hydrodeoxygenation of lignin in presence of HZSM-5 and NaOH, where the water-methanol mixture(1:1) was found to suppress the char formation and improve the product yield and quality compared to pure methanol medium.14 Aqueous phase hydrodeoxygenation of 2-methoxyl-4-allylphenol as a lignin model was studied by Zhang et al. for different ratios of (Si/Al) on HZSM-5 at 240°C and 5 MPa. The best result was obtained by the lowest ratio: (Si/Al=12.5), where the acidity of zeolite increased and the best reaction performance with 86% conversion and 73% selectivity to liquid hydrocarbons was achieved.13 Feng et al. explored different metals on nickel based catalysts for hydrodeoxygenation of 4-propylphenol into n-propyl benzene in aqueous phase. Re-Ni/AC and Re-Ni/SiO2 showed high selectivity to n-propylbenzene, whereas Re-Ni/Al2O3 shifted the product selectivity to oxygenated compounds. The result indicated that adding Re to Ni/ZrO2 improved the catalysts activity significantly.19 Shabatai et al. introduced a patented process to convert lignin into alkylbenzenes which are useful compounds for enhancing the octane level of petroleum derived fuels. This process starts with depolymerization of lignin in basic water medium and finishes by hydroprocessing of depolymerized lignin.20 In parallel with biocrude processing in water, heavy oil upgrading in aqueous phase has also been explored. Fedyaeva et al. studied upgrading of bitumen in supercritical water (SCW) inside a tubular reactor where the highest liquid selectivity was achieved at 400°C to 500°C and pressure of 30 MPa. It was reported that desulphurization was maximized at temperatures above 600°C.21 Zhu et al. concluded that in pyrolysis of heavy oil in SCW without catalyst, free hydrocarbon radicals are perfectly stabilized and coke formation is diminished while, by adding di-tert-butyl proxide (DTBP) to the water medium, coke formation disappears.22 The same 4 ACS Paragon Plus Environment

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behavior of water as a stabilizer is reported by Sato et al. for upgrading of asphalt in water close to critical condition in absence of external hydrogen where asphaltenes conversion, gas yield and sulfur removal all improved by increasing the temperature.11 In the presence of metallic catalyst with hydrogenation function, the role of external hydrogen becomes more important since the hydrogen molecules are dissociated on the catalyst’s surface.23 In the work of Ates et al. stability of three different catalysts (MoS2, MoO3 and ZrO) was studied through the desulfurization of Arabian Heavy oil (AH) in SCW. The experiments were carried out in a batch reactor at 400°C and 25 MPa. Analysis after the reaction showed that MoS2 structure remained unchanged after reaction while MoO3 and ZnO crystal structures altered. AH sulfur removal enhanced 6% in presence of MoS2 compared to non-catalytic reaction.24 The proposed pathway for asphaltene conversion in this research consists of two steps as shown in Figure 1. In the first part, asphaltene is solubilized in water with wet oxidation reaction where the feedstock of hydroprocessing reaction is produced. The aim of this step is preparing the appropriate reaction medium for asphaltene by eliminating the problems caused by the solid virgin asphaltene, including tremendous viscosity and high rate of coke formation. Having asphaltene solubilized in water obviates its transportation and plugging issues. Furthermore, through the reaction of accessible asphaltene particles in water, molecular diffusivity and mass transfer limitations improve and the coke formation diminishes. Wet oxidation reaction is widely practiced in wastewater applications. The performance of this reaction is mainly reported in the form of TOC (Total Organic Carbon) or COD (Chemical Oxygen Demand) removal. Air or oxygen can be used as an oxidizing agent, where the reaction condition stays within the range of 150-325oC and total pressure of 2-17.5 MPa.25 The well-known Zimpro process is the first commercialized application developed for non5 ACS Paragon Plus Environment

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catalytic wet air oxidation in a bubble column reactor at low pressure.26 In asphaltene wet oxidation, solubilization occurs through reactions where solubilized asphaltene is the intermediate product identified as SAW and CO2 is the main gas product, as shown Figure 2. After solubilizing asphaltene in water via wet oxidation, the second step is hydroprocessing of SAW to upgrade the oxy-asphaltene molecules into value added products as shown in Figure 1. Supported bimetallic catalysts (binary combination of Ni/Mo/Co/W) over gamma alumina are well known particles for heavy oil hydrotreating and a better activity can be achieved by using the metals in sulfide state rather than oxide phase.27 A pre-sulfided NiMo/γAl2O3 was used as a catalyst for hydroprocessing experiments. The current research is focused on hydroprocessing of solubilized asphaltene in aqueous phase which is the first attempt on hydroprocessing study of this type of feedstock. Due to the novelty of research and lack of similar works, the reaction pathway and the nature of reaction products is unknown. Therefore in the first step, the feedstock of hydroprocessing, solubilized asphaltene in water, is characterized and the effect of SAW preparation conditions on hydroprocessing results is evaluated. Furthermore, the products of SAW after hydroprocessing are identified and effects of several parameters such as SAW concentration, initial hydrogen pressure and catalyst amount on hydroprocessing are discussed. Experimental section Wet oxidation experiments: Asphaltene was precipitated with normal pentane (> 99.0%, Sigma-Aldrich) from the vacuum residue fraction of Alberta Athabasca Bitumen. The elemental analysis of virgin asphaltene is reported in Table 1. The carbon and hydrogen content of the sample was 6 ACS Paragon Plus Environment

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determined with a LECO 628 analyzer while nitrogen and sulfur contents were measured with an Antek 9000 analyzer. Wet oxidation runs were conducted in a 550 ml Parr batch reactor (Model 4575B, HP/HT Pressure Reactor). 4 grams of asphaltene with 156 grams of water were poured in the reactor and 8 ml of 5.0N NaOH aqueous solution (Aldrich) was added. Prior to the experiments, a leak test was performed with nitrogen at 200 psi above the final reaction pressure. After completion of the leak test the vessel was pressurized with oxygen (99.9% ultra-high purity, Praxair) to 1000 psig at room temperature and the mixing rate was set to 1000 rpm. Finally the system was heated up to the set point temperature. After reaction, the vessel was quenched and the produced gas was collected and analyzed via gas chromatography. The analyses were carried out with a SRI 8610C Multiple Gas #3 gas chromatograph (3’ molecular sieve / 6’ Hayesep-D columns) provided with a TCD detector. GCs temperature holds on 42oC for 10 minutes, then increases to 200oC with a rate of 20oC/min. After gas collection, the reactor was opened and the remaining solid was separated by vacuum filtration. The filtered SAW solution was analyzed with a Shimadzu Total Organic Carbon Analyzer (TOC-V CPH/CPN) to measure the Total Carbon (TC), Total Organic Carbon (TOC) and Inorganic Carbon (IC) in aqueous phase. Standard solutions of sodium hydrogen carbonate and potassium hydrogen phthalate were prepared and used to calibrate the IC and TC measurements. All the calculations including conversion, selectivity and mass balances are conducted based on the amount of carbon in feed and products. The conversion is determined by comparing the carbon content of asphaltene with the carbon content of remaining solids after reaction; the liquid yield is calculated by dividing the amount of solubilized carbon in water to the carbon content of initial asphaltene. A schematic procedure of product separation and characterization of wet oxidation experiments is presented in Figure 3. 7 ACS Paragon Plus Environment

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Hydroprocessing experiments: To conduct hydroprocessing experiments, a 100 ml Micro 4598 Parr batch reactor with the possibility of controlling temperature, pressure and stirring rate was used. 25 g of the SAW, produced from previous wet oxidation experiments were added to the reactor with the desired amount of catalyst. After conducting the leak test following the earlier described procedure, the reactor was pressurized with hydrogen (99.9% ultra-high purity, Praxair) at room temperature and the stirring rate was set to 500 rpm. Finally the reactor was heated up to reach the set point temperature and reaction started. A similar gas chromatograph as described in the previous section, but in this case with multiple detectors, was implemented to analyze the produced gases. Hydrogen analysis was conducted by a HID detector while light hydrocarbons as well as CO and CO2 were detected by TCD. The GC measurement was repeated 4 times for each sample, with the average relative error lower than 1%. The liquid products from hydroprocessing were extracted by adding 25 ml of CS2 (>99.9%, Sigma-Aldrich) to the solubilized materials in water obtained after reaction. The two phase liquid mixture was stirred for 60 minutes at 1000 rpm to ensure the total extraction of produced organic compounds from the aqueous phase towards the CS2 phase. The extracted hydrocarbons with CS2 were later analyzed by High Temperature Simulated Distillation (HTSD) carried out with an Agilent 6890N gas chromatograph following the ASTM D 7169-05 method. The detailed description of this method can be found elsewhere.28 Liquid products were also quantified via HTSD by using a calibration curve prepared with four different concentrations of known hydrocarbon solutions in CS2. Validity of this calibration is based on the fact that after hydroprocessing most produced species are hydrocarbons, i.e., compounds containing carbon 8 ACS Paragon Plus Environment

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and hydrogen but not oxygen anymore. This aspect will be discussed later in greater detail (see Figure 16-b and related discussion). The amount of carbon in reacted SAW after liquid extraction was measured with TOC analyzer and compared with carbon content of fresh SAW before hydroprocessing. TOC analyses were conducted 3 times for each sample and the final results are reported with average relative errors lower than 2%. A schematic representation of product separation and detailed characterization of hydroprocessing products is presented in Figure 4. The average of mass balances calculated based on the weight of carbon before and after experiments, was higher than 95% for all the runs. The conversion and product yields were calculated using equations 1 to 3.

= 100 × ( − )

! " =

# " =

100 × ( ! )

100 × ( $! )

(1)

(2)

(3)

Other characterization methodologies Beside the previously mentioned methods, the following analyses were also performed on the feed and products to have a better understanding on reaction mechanisms.

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GC/MS: The produced organics extracted with CS2 were analyzed with Shimadzu GCMS-QP5000 instrument provided with AOC-20i auto-sampler. For each run, 2 ul of sample were injected through normal injection after 5 times rinsing with solvent and 3 times rinsing with sample. The GCs temperature stays at 40oC during 2 minutes, then reaches to 250oC at a 10oC/min ramp and finally to 300oC at a 20oC/min ramp, where helium was used as carrier gas (11 kPa, 1.5 mL/min and split ratio of 25). The mass spectrometer was operated in EI ionization mode, with a scan range of 35-300 m/z and 0.56 second scan interval. The interface heated at 310oC, was coupled to the GC-17A equipped with an Agilent DB-5 column (30m x 0.25 m i.d. and 0.25 um d.f.). NIST MS spectra library was used to identify the compounds in the liquid sample. The GC/MS analysis was also carried out for the fresh SAW before hydroprocessing. Aqueous samples such as SAW are difficult to be directly analyzed with GSMS equipment unless guard column is inserted ahead of the analytical column. In fact, the content of aqueous samples should be extracted with another solvent such as CS2 for being analyzed. For the case of fresh SAW, the majority of solubilized asphaltene molecules remained in aqueous phase after extraction probably due to the high polarity of SAW molecules. Although, the GC/MS was only performed on the CS2 soluble fraction of fresh SAW, several important results were obtained which improved the understanding of SAW fraction. Infrared spectroscopy: The solubilized asphaltene in water was dried at 80oC overnight in a vacuum oven. The solids were further characterized by DRIFTS analysis (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) using a Nicolet 6700 FTIR from Thermo Electron Corporation,


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provided with smart diffuse reflectance cell. The KBr powder was initially run to define the background (blank), then the sample dispersed in KBr was analyzed acquiring 128 scans with a resolution of 2 cm-1. The pH of the sample solution before drying was determined to be > 7.4 as will be discussed in an ensuing section. TGA: Thermogravimetric analysis was carried out with a TGA/DSC analyzer (SDT Q600, TA Instrument) to measure the carbon content for the mixture of catalyst plus precipitated solid recovered after hydroprocessing. To avoid the diffusion limitation, a small amount of sample (~5 mg) was put on the alumina crucible holder, then it was heated up from equilibrium temperature at 50oC to 900oC by a linear rate of 10oC/min while air flow rate was kept at 100 cc/min. The Pfeiffer OmniStar GSD 301 Quadrupole Mass Spectrometer with ability of detecting masses up to 200 amu and simultaneous data acquisition of 21.6 seconds per cycle was also coupled to TGA. The evolved gas from TGA entered the MS through a capillary stainless steel tubing heated to 200oC. Catalyst preparation The NiMo/γ-Al2O3 was prepared following the dry impregnation method: aqueous solutions of nickel (II) acetate tetra hydrate (Aldrich) and ammonium heptamolybdate (BDH) were prepared separately and added to the finely grounded gamma alumina support (γ-Al2O3 provided in spherical shape, by Sasol). After drying the catalyst at room temperature, it was calcined during 6 hours at 500oC. To sulfide the catalyst, 2 grams of solid were added to 30 ml of a 10% CS2 in Decahydronaphthalene (>99%, Sigma-Aldrich) solution. The sulfiding reaction was conducted at 350oC during 6 hours with a stirring rate of 500 rpm using a 100ml Parr reactor


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with initial hydrogen pressure of 200 psig at 25oC. After sulfidation, the catalyst was washed with toluene and finally dried at room temperature. To avoid the reoxidation of the catalyst by air, it was kept in toluene solution before using for tests. The textural properties of fresh catalyst prior to sulfidation including BET surface area, pore size and pore volume are reported in Table 2. Results and discussion: FTIR analyses: Mechanism of asphaltene solubilization in water through oxidation Infrared spectra of asphaltene solubilized in water via wet oxidation at 240oC during 2 hours and the virgin asphaltene before oxidation are compared in Figure 5. In the presence of oxygen in aqueous phase, the asphaltene particles are fully oxidized and transformed to organic species with carboxylic functions similar to humic/fulvic acids. The FTIR spectra of humic acids containing several carboxylic functional groups can be found elsewhere.29,30 The acids produced during the asphaltenes oxidation are sparingly soluble in water; however, in the presence of bases such as sodium hydroxide, the solubilization occurs following the acid / base neutralization mechanism and finally the hydrocarbon salts soluble in water are created which can be compared to salts of humic acids based on IR spectra. The Infrared of natural humic salts is presented in Figure 5-C. The FTIR comparison of humic salts with solubilized asphaltene in Figure 5 shows the similarity of absorption bands in both compounds. Increasing the solubility of oxygencontaining species in water in presence of bases has been confirmed in other studies as well.12,31 Patil et al. reported that NaOH enhanced the solubility of lignin in water while no monomer products were detected by GC/MS suggesting transformation of lignin to salts that were soluble in water.12


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In Figure 5-A, the alkyl group bands including C-H stretch (2850-2950 cm-1) and C-H asymmetric and symmetric bending (1453 and 1376 cm-1) is detected in virgin asphaltene. Furthermore the aromatic function bands such as C-H stretch (the slight shoulder of alkyl group at 3030 cm-1), C=C skeletal stretch at 1600 cm-1 and three bands of mono, di and tri-substituted for C-H out of plane bending (747, 811 & 863 cm-1) can be easily observed in the virgin asphaltene. The small band at 1031cm-1 in the virgin asphaltene corresponds to sulfoxide species.32 Carbognani and Buenrostro evidenced the presence of sulfoxide for the asphaltene fractions that are precipitated in presence of oxygen.33 FTIR spectra for asphaltene solubilized in water presented in Figure 5-B, shows the presence of oxygen group functions such as the intense-broad O-H band in the region of 30003700 cm-1, accompanied with a complex carbonyl band at 1733 cm-1 ,which can be partially ascribed to carboxylic acid. Two important signals at 1414 cm-1 and 1584 cm-1 represent carboxylate anions (C=O asymmetric and symmetric stretch vibration) in asphaltene structure after reaction, which evidences the hypothesis of asphaltene solubilization by neutralization during wet oxidation with sodium hydroxide. The same bands of hydroxyl, carboxyl and carboxylate is also visible in the natural humic salts spectrum presented in Figure 5-C. The IR band appearing at 1137cm-1 could be representative of sulfones (O=S=O) or C-OC groups, where the chance of both group functions existence is high via oxidation reactions. Detection of sulfonic compounds at low temperature oxidation of heavy oil in presence of water was also reported in the work of Lee et al.34 It should be noted that the sulfur containing functional groups in Figure 5 are less intense in the humic salts compared to SAW fraction.


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Effect of oxidation conditions on further hydroprocessing reaction A set of wet oxidation experiments was carried out to verify the influence of oxidation conditions on the further hydroprocessing results. The reaction conditions including residence time and temperature as well as results of conversion and solubility (liquid yield) for wet oxidation experiments are reported in Table 3. The liquid yield of oxidation stayed around 50% for all conditions as shown in Table 3. In fact, the solubility level of asphaltene in water was fixed for all oxidation experiments to have the same amount of carbon in the prepared SAW since the variation of this parameter (solubility level in water) can affect the further hydroprocessing. The reaction pathway of wet oxidation is mostly described by triangular lumped model presented in Figure 2 which includes two parallel paths. The first path is the consecutive reaction where feedstock first converts to intermediate product and finally to CO2. In the second path, the organic feedstock directly oxidizes to CO2.35-37 This means that if residence time or temperature increase individually without changing the other one, the yield to CO2 increases while intermediate product (SAW) is minimized or disappeared. Therefore, temperature and residence time for solubilization reaction shown in Table 3 are coupled in such a way that asphaltene solubilization remains at the same level (for the case that reaction temperature increases, the residence time is decreased to keep the conversion and yield within the previous ranges). For all the wet oxidation experiments, the gas product composition consists of CO2 and CO with high selectivity to carbon dioxide which is a typical gaseous product for wet air oxidation of effluents.37,38 The pH measurement after wet oxidation presented in Table 3 indicates that the amount of NaOH was enough to neutralize the created acidic functions, since it is considerably higher than the pKa of organic acids. 14 ACS Paragon Plus Environment

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After preparing the different SAW samples, a set of hydroprocessing tests was conducted under the fixed conditions reported in Table 4. The results of hydroprocessing experiments reported in Table 5 indicate that conversion stayed within the range of 40% for all SAW samples while the yield of liquid hydrocarbons slightly increased when solubilization temperature varied from 230oC (15.5%) to 240oC(18%). The boiling point distribution of liquid products after hydroprocessing experiments for SAW produced under different oxidation temperatures is presented in Figure 6. The asphaltene molecules that were solubilized in water at higher temperature provide lighter products after hydroprocessing. In other words, higher selectivity to lower boiling point hydrocarbons will be obtained by performing the solubilization reaction at higher temperatures. As shown in Figure 6, after hydroprocessing the amount of naphtha fraction (IBP to 200oC) is about 50% of liquid products for SAW produced at oxidation temperature of 240oC, while just 10% of the liquid fraction obtained from SAW prepared at 215oC, distilled in the naphtha boiling point range. This HTSD analysis confirms that through the first reaction (solubilization of asphaltene in water), oxy-cracking occurs and strengthens by increasing the temperature. At higher temperature, more energy is available to dissociate C-C bonds which facilitates cracking of large molecules towards smaller hydrocarbons. The occurrence of oxy-cracking during the asphaltene solubilization was recently supported with detailed analysis of SAW conducted by mass spectrometry analysis.39 Hydroprocessing of concentrated asphaltene solubilized in Water After the solubilization reaction, the SAW solution can be concentrated without further precipitation of solubilized materials. Higher concentration of solubilized asphaltene in aqueous phase requires less energy to heat up the solution during hydroprocessing and diminishes the water partial pressure at reaction temperature. In Table 6 the results of conversion and product 15 ACS Paragon Plus Environment

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yields for hydroprocessing of different SAW concentrations is presented. All the experiments were carried out at 320oC, 3 h residence time, 0.5 gram of catalyst with 500 rpm mixing rate and initial hydrogen pressure of 600 psig at 25oC. The wet oxidation was conducted and repeated under the same conditions to prepare the required amount of solubilized asphaltenes for this set of experiments. To concentrate the soluble asphaltene in water, rotary evaporation at 70oC was applied. Table 6 indicates that the liquid production declined 7% by increasing the SAW concentration from 8.72g/l (218.2 mg of carbon/25mlCS2) to 84.08g/l (2103 mg of carbon/25mlCS2) while the boiling point distribution of products shown in Figure 8 did not change and distillates quality stayed constant. GC analyses after reaction presented in Figure 9 and Figure 10, show that CO2 was a major component of produced gases, arising from decarboxylation reactions. The low amounts of CO and CH4 shown in Figure 10 could be the result of methanation and water-gas shift reactions. CO2 is the primary gas produced by carboxylic bonds scission, which is a favorable reaction at low temperature hydrocracking.40 The production of similar gas species during upgrading of heavy hydrocarbons in aqueous medium was reported in several published articles.11,12,24,41 Another important observation from hydroprocessing experiments is the increase of solid formation by increasing the SAW concentration. The solid production is increased from 12.5% to 26.0% when increasing the SAW concentration by a factor of 10, as indicated in Figure 7. Precipitation of this solid which in not soluble in water, CS2 or toluene suggests the formation of organic compounds similar to coke, based on these solubility properties. Coke is generally created by condensation of aromatic free radicals produced through the cracking of large molecules at high temperatures. Suppression of coke formation in hydrotreating in presence of 16 ACS Paragon Plus Environment

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solvent was reported in several works.8,11,22,42 In the solvent medium, diffusivity of molecules in reaction media improves, thus hydrogen accessibility to radicals increases which prevents the coke formation.42 The decrease of liquid and gas yield coupled with the enhancement of solid formation by increasing the concentration of SAW, which were observed in Figure 7, indicate that reaction progress is inhibited by limiting factors such as hydrogen through hydroprocessing of high concentrated SAW. As the oxidized asphaltene content increases in the medium, the external hydrogen should be also increased to keep the reaction pathway. In other words, the same amount of hydrogen causing the reaction to proceed under excess amount of hydrogen for nonconcentrated SAW, could play a controlling role for concentrated solution. Lack of hydrogen promotes the coke formation in heavy oil hydrocracking. As shown in Figure 9, the hydrogen content of the gas phase after hydroprocessing decreases by increasing the SAW concentration which indicates the hydrogen incorporation and consumption during the reaction. To verify the limiting effect of external hydrogen, the highest concentration of SAW was chosen and the effect of the hydrogen initial pressure on hydroprocessing of SAW was evaluated. As shown in Figure 11, by increasing the hydrogen pressure, the solid formation decreases from 26.0% at 600 psig initial hydrogen pressure to 9.5 % for an initial hydrogen pressure of 1000 psig. By suppression of solid formation, a slight increase in liquid production is observed simultaneously, confirming the progress of reaction at higher hydrogen pressures. Presence of external hydrogen saturates and stabilizes the produced free radicals of aromatic compounds and diminishes the coke formation. The comparison of HTSD analysis for liquid products shown in Figure 12 reveals that boiling point distribution of liquid products stayed


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relatively constant by variation of initial hydrogen pressure. However, a minor increase in the naphta fraction was achieved in products obtained under higher hydrogen pressure. The same scenario of hydrogen deficiency for concentrated solutions can be applied to catalyst/carbon ratio, where higher concentrations of SAW may require more catalyst in the reaction medium. Comparison of thermal and catalytic reactions shown in Table 7 justifies the progress of reaction in the presence of catalyst where the liquid production increases from 8 % in non-catalytic reaction to 12% in the presence of catalyst. However, the results of experiments carried out with different catalyst amounts illustrated in Figure 13 show that increasing the catalyst amount does not change the product yields and conversion, indicating the excess amount of catalyst under all reaction conditions. The results of TGA coupled with mass spectrometry are presented in Figure 14 and Figure 15. The comparison of weight loss for the fresh presulfided catalyst and the solid sample obtained after hydroprocessing of non-concentrated SAW is shown in Figure 14-a. It should be emphasized that the solid sample after reaction is not only catalyst and it contains the mixture of spent catalyst and solid organic compounds produced after hydroprocessing. The formation of carbonaceous species is confirmed by the weight loss of solid sample after reaction being 8% higher than the weight loss for the fresh catalyst in Figure 14-a. The amount of mass loss up to 200oC was ignored since it is related to the evaporation of water content of samples. Figure 14-b indicates the weight loss and its derivative (rate of weight loss) for the fresh presulfided catalyst. It should be noted that the TGA was carried out under the presence of air; thus, the oxidation and combustion occurred in parallel with pyrolysis throughout the analyses. By comparing the current TGA analyses with the Temperature Programmed Oxidation (TPO) studies of fresh presulfided and spent NiMo/Al2O3 catalyst, several similarities can be found.43-48 18 ACS Paragon Plus Environment

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The first mass derivatives peak observed in the fresh presulfided catalyst at 265oC in Figure 14-b can be attributed to the oxidation of molybdenum sulfide. Marafi et al. evidenced the MoS2 oxidation at 265oC by detecting SO2 in TPO analysis of fresh presulfided Mo/Alumina.45 The SO2 peak was also detected by the mass spectrometer at 265oC on fresh presulfided catalyst as shown in Figure 14-c, which confirms this hypothesis. The second mass derivative peak in the fresh presulfided catalyst with a maximum at 450oC can be referred to two different sources. First, it can be partially due to the oxidation of NiMoS and NiS phases which was evidenced by Zeuthen et al. during the study of NiMo/Al2O3 with different Ni/Mo ratios.44 The authors reported that the peak at 450oC was absent in presulfided Mo/Alumina catalyst but clearly appeared in the presence of Ni and Mo together on the catalyst. The second SO2 peak in Figure 14-c is also located at the same temperature which justifies the oxidation of sulfur species on fresh sulfided catalyst in this region. The mass derivative peak in the fresh catalyst (450oC) in Figure 14-b can be also assigned

to

the

combustion

of

carbonaceous

species

originating

from

the

CS2-

decahydronaphthalene solution used for catalyst sulfidation. The CO2 peak at 450oC in Figure 14-c confirms the presence of carbonaceous material on fresh sulfided catalyst. The combustion of soft coke on NiMo/Alumina is reported to occur in this region45,48 which is also supported by CO2 detection at the same temperature in this work. For the solid sample after reaction the combustion of carbonaceous material is also detected at a temperature of 450oC as shown in Figure 15-a and Figure 15-b. An additional mass derivative peak at higher temperature is also observed in the solid sample after reaction (540oC) in Figure 15-a that can be attributed to the combustion of organic material similar to hard coke on NiMo/Alumina. The transformation of this type of coke over NiMo/Al2O3 was detected at 19 ACS Paragon Plus Environment

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similar temperatures elsewhere.45,48 At 540oC the CO2 and SO2 peaks are detected together as shown in Figure 15-b, suggesting the combustion of sulfur containing organic compounds. It should be noted that combusted compounds after reaction are not necessarily deposited on the catalyst’s sites and could be present in solid phase without physical or chemical bonds to the catalyst. The comparison of TGA analysis for the pure asphaltene and remaining solid after reaction shown in Figure 15-c indicates that the major mass loss for pure asphaltenes occurs at similar temperatures (the weight derivatives peaks are located at the same temperatures in pure asphaltene and solid sample collected after reaction as presented in Figure 15-c). Deoxygenation of asphaltene solubilized in water through hydroprocessing GC/MS results of solubilized asphaltene (product of wet oxidation) and the liquid product obtained after hydroprocessing of non-concentrated SAW are presented in Figure 16. Figure 16-a illustrates that the CS2 soluble fraction of fresh SAW include a series of carboxylic acids with a wide range of carbon numbers spanning from 6 up to 22 carbon atoms. This result supports the work of Klenke et al. on alkaline wet oxidation of wheat straw where carboxylic acids were found as the main products beside water and CO2.38 The mass chromatogram presented in Figure 16-a also supports the FTIR characterization of fresh SAW shown in Figure 5-B where important contribution of free carboxyl acid functions was evidenced. It should be noted that only the CS2 soluble portion of SAW was analyzed before hydroprocessing, because the major proportion corresponding to carboxylic salts (see Figure 5-B) are not soluble in this solvent and remain in the aqueous phase. The components identification of fresh SAW is reported in Table 8. Liquid products after hydroprocessing are mainly in the form of two ring hydrocarbons with higher selectivity to hydrogenated molecules (larger peak of decalin compared to smaller peak of naphthalene in Figure 16-b). The observed naphthalene and fluorene peaks in Figure 1620 ACS Paragon Plus Environment

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b were also found by Han et al. in products of coal tar upgrading in supercritical water without external hydrogen, accompanied with other aromatic compounds with 1 to 4 rings.49 For the case of SAW hydroprocessing, the yield of saturated ring chemicals increases due to the presence of hydrogen in the medium. The low content of oxygenates in the liquid product distribution (detected phenolic groups in Figure 16-b) indicates the deoxygenation of products during hydroprocessing in water. In several works cyclic and phenolic compounds were found as a products of lignin hydrodeoxygenation reaction in aqueous phase.13,14,18,19 It is important at this point to be aware that GCMS is only able to provide results for small molecular weight compounds (< C30), thus nothing can be inferred for larger compounds if they are present. Through the hydroprocessing reaction, the large molecules of oxygenated asphaltene were hydrogenated and broken into smaller hydrocarbons. For instance, the benzothiophene and methyl-benzothiophene that are observed in trace amount in Figure 16-b were probably dissociated from solubilized asphaltene during hydroprocessing and appear in liquid products. This type of sulfur compounds can be abundantly found in Athabasca asphaltene.50 The hydrocarbons identified in the liquid product after hydroprocessing are summarized in Table 9. It should be mentioned that obtaining a high conversion and liquid yield of reaction was not the motivation of this research as the hydroprocessing experiments were carried out at moderate conditions below 320oC. In fact, this study was focused on understanding the reaction pathway in aqueous medium and evaluating the effective parameters of reaction. However, the low liquid yield of hydroprocessing even for non-concentrated solutions that were observed in all experiments shows that hydrogenation needs to be further increased. Lack of hydrogenation might be due to inefficiency of catalyst in aqueous phase and/or inaccessibility of hydrogen 21 ACS Paragon Plus Environment

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molecules to reactants (the comparison of thermal and catalytic reaction shown in Table 7 indicates that reaction performance does not progress significantly in presence of catalyst). Hydrogen donation ability of water as a solvent in aqueous reaction medium is discussed in several works30,51,52 and some authors claim that reactivity of water-hydrogen can be higher than external hydrogen.23 Using the advantage of the reaction in aqueous medium where water supplies the hydrogen for hydrogenation could be a further topic of this research, making the reaction more efficient with lower or even without the addition of external hydrogen. In case that water-hydrogen does not activate thermally by free radical or ionic mechanisms, applying a catalyst with water splitting functions can eliminate the needs of external hydrogen. Characteristics of such catalysts and their application for heavy oil upgrading can be found elsewhere.53-55 Conclusions The solubilized asphaltene in water (SAW) is the feedstock of hydroprocessing experiments, which was produced by asphaltene oxidation in aqueous phase in the presence of NaOH. The FTIR characterization confirmed the presence of carboxylic and carboxylate functional groups in the structure of solubilized asphaltene in water. This was also supported by detecting several carboxylic acids in CS2 soluble fractions of fresh SAW through GC/MS analysis. Hydroprocessing of SAW at 320oC and 3 h residence time reveals that the quality of hydroprocessing products improved for the cases that feedstock (SAW) was prepared at higher oxidation temperatures. The hydrogen deficiency in hydroprocessing of high concentrated SAW was improved by increasing the initial hydrogen pressure from 600 psig to 1000 psig where the liquid yield increased 4% and solid yield declined 16.5%. The comparison of thermal and catalytic SAW 22 ACS Paragon Plus Environment

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hydroprocessing indicated that the liquid yield increased around 5% for catalytic reaction but the increase of catalyst amount in the reaction medium did not affect the reaction progress. Disappearance of carboxylic acids in the mass chromatogram of liquid products and detection of CO2 as a main produced gas evidences that decarboxylation is a dominant reaction during hydroprocessing and oxygen removal is mostly occurring through this reaction. The feasibility of producing value added products through the hydroprocessing of oxygenated asphaltene in aqueous phase was confirmed. Two fused ring hydrocarbons were found as major compounds in the lighter fraction of liquid product from SAW hydroprocessing, while low contents of oxygenated hydrocarbons from the phenol family were also detected. Author information Corresponding Author *E-mail: [email protected] Phone: +1 (403) 210-9588 Note: The authors declare no competing financial interest.

Acknowledgement The authors gratefully acknowledge the financial support by Nexen CNOOC ltd, Alberta Innovates-Energy and Environment Solutions (AIEES) and Natural Sciences and Engineering Research Council of Canada (NSERC) provided through the Industrial Research Chair in Catalysis for Bitumen Upgrading.


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References (1) Rettger, P.; Arnold, J.; Jancker, A.; Cathro, D. C. Gasification in the canadian oil sands: the long lake integrated upgrading project. Gasification Technologies Conference 2004. (2) BP Statistical Review of World Energy 2014. (3) Long, R. B., The Concept of Asphaltenes. In Chemistry of Asphaltenes, American Chemical Society: 1982; Vol. 195, pp 17-27. (4) Mullins, O. C.; Sabbah, H.; Eyssautier, J.; Pomerantz, A. E.; Barré, L.; Andrews, A. B.; Ruiz-Morales, Y.; Mostowfi, F.; McFarlane, R.; Goual, L.; Lepkowicz, R.; Cooper, T.; Orbulescu, J.; Leblanc, R. M.; Edwards, J.; Zare, R. N. Advances in Asphaltene Science and the Yen–Mullins Model. Energy & Fuels 2012, 26 (7), 3986-4003. (5) Tanaka, R.; Sato, S.; Takanohashi, T.; Hunt, J. E.; Winans, R. E. Analysis of the Molecular Weight Distribution of Petroleum Asphaltenes Using Laser Desorption-Mass Spectrometry. Energy & Fuels 2004, 18 (5), 1405-1413. (6) Branco, V. A. M.; Mansoori, G. A.; De Almeida Xavier, L. C.; Park, S. J.; Manafi, H. Asphaltene flocculation and collapse from petroleum fluids. Journal of Petroleum Science and Engineering 2001, 32 (2–4), 217-230. (7) Yarranton, H. W.; Ortiz, D. P.; Barrera, D. M.; Baydak, E. N.; Barré, L.; Frot, D.; Eyssautier, J.; Zeng, H.; Xu, Z.; Dechaine, G.; Becerra, M.; Shaw, J. M.; McKenna, A. M.; Mapolelo, M. M.; Bohne, C.; Yang, Z.; Oake, J. On the Size Distribution of Self-Associated Asphaltenes. Energy & Fuels 2013, 27 (9), 5083-5106. (8) Vilcáez, J.; Watanabe, M.; Watanabe, N.; Kishita, A.; Adschiri, T. Hydrothermal extractive upgrading of bitumen without coke formation. Fuel 2012, 102, 379-385. (9) Timko, M. T.; Ghoniem, A. F.; Green, W. H. Upgrading and desulfurization of heavy oils by supercritical water. The Journal of Supercritical Fluids 2015, 96, 114-123. (10) Sato, T.; Tomita, T.; Trung, P. H.; Itoh, N.; Sato, S.; Takanohashi, T. Upgrading of Bitumen in the Presence of Hydrogen and Carbon Dioxide in Supercritical Water. Energy & Fuels 2013, 27 (2), 646-653. (11) Sato, T.; Adschiri, T.; Arai, K.; Rempel, G. L.; Ng, F. T. T. Upgrading of asphalt with and without partial oxidation in supercritical water. Fuel 2003, 82 (10), 1231-1239. (12) Patil, P. T.; Armbruster, U.; Richter, M.; Martin, A. Heterogeneously Catalyzed Hydroprocessing of Organosolv Lignin in Sub- and Supercritical Solvents. Energy & Fuels 2011, 25 (10), 4713-4722. (13) Zhang, C.; Xing, J.; Song, L.; Xin, H.; Lin, S.; Xing, L.; Li, X. Aqueous-phase hydrodeoxygenation of lignin monomer eugenol: Influence of Si/Al ratio of HZSM-5 on catalytic performances. Catalysis Today 2014, 234 (0), 145-152. (14) Singh, S. K.; Ekhe, J. D. Solvent effect on HZSM-5 catalyzed solvolytic depolymerization of industrial waste lignin to phenols: superiority of the water-methanol system over methanol. RSC Advances 2014, 4 (95), 53220-53228. (15) Akizuki, M.; Fujii, T.; Hayashi, R.; Oshima, Y. Effects of water on reactions for waste treatment, organic synthesis, and bio-refinery in sub- and supercritical water. J Biosci Bioeng 2014, 117 (1), 10-8. (16) Golombok, M.; Ineke, E. Oil mobilisation by subcritical water processing. Journal of Petroleum Exploration and Production Technology 2013, 3 (4), 255-263. (17) Yan, N.; Yuan, Y.; Dykeman, R.; Kou, Y.; Dyson, P. J. Hydrodeoxygenation of Lignin-Derived Phenols into Alkanes by Using Nanoparticle Catalysts Combined with Brønsted Acidic Ionic Liquids. Angewandte Chemie International Edition 2010, 49 (32), 5549-5553. (18) Mu, W.; Ben, H.; Du, X.; Zhang, X.; Hu, F.; Liu, W.; Ragauskas, A. J.; Deng, Y. Noble metal catalyzed aqueous phase hydrogenation and hydrodeoxygenation of lignin-derived pyrolysis oil and related model compounds. Bioresource Technology 2014, 173 (0), 6-10. (19) Feng, B.; Kobayashi, H.; Ohta, H.; Fukuoka, A. Aqueous-phase hydrodeoxygenation of 4propylphenol as a lignin model to n-propylbenzene over Re-Ni/ZrO2 catalysts. Journal of Molecular Catalysis A: Chemical 2014, 388–389 (0), 41-46.


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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 42

(20) Shabtai, J.; Zmierczak, W.; Chornet, E.; Johnson, D. Process for converting lignins into a high octane blending component. Patent US20030100807 A1, May 29,2003. (21) Fedyaeva, O. N.; Shatrova, A. V.; Vostrikov, A. A. Effect of temperature on bitumen conversion in a supercritical water flow. The Journal of Supercritical Fluids 2014, 95 (0), 437-443. (22) Zhu, C.-C.; Ren, C.; Tan, X.-C.; Chen, G.; Yuan, P.-Q.; Cheng, Z.-M.; Yuan, W.-K. Initiated pyrolysis of heavy oil in the presence of near-critical water. Fuel Processing Technology 2013, 111, 111117. (23) Furimsky, E. Hydroprocessing in Aqueous Phase. Industrial & Engineering Chemistry Research 2013, 52 (50), 17695-17713. (24) Ates, A.; Azimi, G.; Choi, K.-H.; Green, W. H.; Timko, M. T. The role of catalyst in supercritical water desulfurization. Applied Catalysis B: Environmental 2014, 147 (0), 144-155. (25) Lefèvre, S.; Boutin, O.; Ferrasse, J.-H.; Malleret, L.; Faucherand, R.; Viand, A. Thermodynamic and kinetic study of phenol degradation by a non-catalytic wet air oxidation process. Chemosphere 2011, 84 (9), 1208-1215. (26) Kolaczkowski, S. T.; Plucinski, P.; Beltran, F. J.; Rivas, F. J.; McLurgh, D. B. Wet air oxidation: a review of process technologies and aspects in reactor design. Chemical Engineering Journal 1999, 73 (2), 143-160. (27) Ancheyta, J.; Rana, M. S.; Furimsky, E. Hydroprocessing of heavy petroleum feeds: Tutorial. Catalysis Today 2005, 109 (1–4), 3-15. (28) Carbognani, L.; Lubkowitz, J.; Gonzalez, M. F.; Pereira-Almao, P. High Temperature Simulated Distillation of Athabasca Vacuum Residue Fractions. Bimodal Distributions and Evidence for Secondary “On-Column” Cracking of Heavy Hydrocarbons. Energy & Fuels 2007, 21 (5), 2831-2839. (29) Senesi, N.; D'Orazio, V.; Ricca, G. Humic acids in the first generation of EUROSOILS. Geoderma 2003, 116 (3-4), 325-344. (30) Rodriguez, F. J.; Schlenger, P.; Garcia-Valverde, M. Monitoring changes in the structure and properties of humic substances following ozonation using UV-Vis, FTIR and H NMR techniques. Sci Total Environ 2015, 541, 623-637. (31) Konnerth, H.; Zhang, J.; Ma, D.; Prechtl, M. H. G.; Yan, N. Base promoted hydrogenolysis of lignin model compounds and organosolv lignin over metal catalysts in water. Chemical Engineering Science 2015, 123, 155-163. (32) Akrami, H. A.; Yardim, M. F.; Akar, A.; Ekinci, E. FT-i.r. characterization of pitches derived from Avgamasya asphaltite and Raman-Dinçer heavy crude. Fuel 1997, 76 (14–15), 1389-1394. (33) Carbognani, L.; Buenrostro-Gonzalez, E. Oxidation Evidenced during Hydrocarbon Preparative Fraction Isolation. Intrinsic Stability Aspects Affecting Crude Oils. Energy & Fuels 2006, 20 (3), 11371144. (34) Lee, D. G.; Noureldin, N. A. Effect of water on the low-temperature oxidation of heavy oil. Energy & Fuels 1989, 3 (6), 713-715. (35) Luck, F. Wet air oxidation: past, present and future. Catalysis Today 1999, 53 (1), 81-91. (36) Pintar, A.; Berčič, G.; Besson, M.; Gallezot, P. Catalytic wet-air oxidation of industrial effluents: total mineralization of organics and lumped kinetic modelling. Applied Catalysis B: Environmental 2004, 47 (3), 143-152. (37) Sánchez-Oneto, J.; Portela, J. R.; Nebot, E.; Martı́nez-de-la-Ossa, E. J. Wet air oxidation of longchain carboxylic acids. Chemical Engineering Journal 2004, 100 (1–3), 43-50. (38) Klinke, H. B.; Ahring, B. K.; Schmidt, A. S.; Thomsen, A. B. Characterization of degradation products from alkaline wet oxidation of wheat straw. Bioresource Technology 2002, 82 (1), 15-26. (39) Silva, R. C.; Radović, J. R.; Ahmed, F.; Ehrmann, U.; Brown, M.; Carbognani Ortega, L.; Larter, S.; Pereira-Almao, P.; Oldenburg, T. B. P. Characterization of Acid-Soluble Oxidized Asphaltenes by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: Insights on Oxycracking Processes and Asphaltene Structural Features. Energy & Fuels 2016, 30 (1), 171-179. (40) Soodhoo, K.; Phillips, C. R. Non-catalytic hydrocracking of asphaltenes: 1. Product distributions. Fuel 1988, 67 (3), 361-374.


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(41) Wan, H.; Chaudhari, R. V.; Subramaniam, B. Aqueous Phase Hydrogenation of Acetic Acid and Its Promotional Effect on p-Cresol Hydrodeoxygenation. Energy & Fuels 2013, 27 (1), 487-493. (42) Xu, C.; Su, H.; Ghosh, M. Hydro-treating of Asphaltenes in Supercritical Toluene with MgOSupported Fe, Ni, NiMo, and CoMo Catalysts. Energy & Fuels 2009, 23 (7), 3645-3651. (43) Bartholdy, J.; Zeuthen, P.; Massoth, F. E. Temperature-programmed oxidation studies of aged hydroprocessing catalysts. Applied Catalysis A: General 1995, 129 (1), 33-42. (44) Zeuthen, P.; Blom, P.; Muegge, B.; Massoth, F. E. Temperature-programmed sulfidation and oxidation of Ni-Mo/alumina catalysts and reaction with ammonia. Applied Catalysis 1991, 68 (1), 117130. (45) Marafi, A.; Hauser, A.; Stanislaus, A. Deactivation patterns of Mo/Al2O3, Ni–Mo/Al2O3 and Ni– MoP/Al2O3 catalysts in atmospheric residue hydrodesulphurization. Catalysis Today 2007, 125 (3–4), 192-202. (46) Koizumi, N.; Urabe, Y.; Inamura, K.; Itoh, T.; Yamada, M. Investigation of carbonaceous compounds deposited on NiMo catalyst used for ultra-deep hydrodesulfurization of gas oil by means of temperature-programmed oxidation and Raman spectroscopy. Catalysis Today 2005, 106 (1–4), 211-218. (47) Zeuthen, P.; Bartholdy, J.; Massoth, F. E. Temperature-programmed oxidation studies of aged Vcontaining hydroprocessing catalysts. Applied Catalysis A: General 1995, 129 (1), 43-55. (48) Torres-Mancera, P.; Rayo, P.; Ancheyta, J.; Marroquín, G.; Centeno, G.; Alonso, F. Characterization of spent and regenerated catalysts recovered from a residue hydrotreating bench-scale reactor. Fuel 2015, 149, 143-148. (49) Han, L.; Zhang, R.; Bi, J. Experimental investigation of high-temperature coal tar upgrading in supercritical water. Fuel Processing Technology 2009, 90 (2), 292-300. (50) Peng, P.; Morales-Izquierdo, A.; Hogg, A.; Strausz, O. P. Molecular Structure of Athabasca Asphaltene: Sulfide, Ether, and Ester Linkages. Energy & Fuels 1997, 11 (6), 1171-1187. (51) Dutta, R. P.; McCaffrey, W. C.; Gray, M. R.; Muehlenbachs, K. Thermal Cracking of Athabasca Bitumen: Influence of Steam on Reaction Chemistry. Energy & Fuels 2000, 14 (3), 671-676. (52) Morimoto, M.; Sugimoto, Y.; Saotome, Y.; Sato, S.; Takanohashi, T. Effect of supercritical water on upgrading reaction of oil sand bitumen. The Journal of Supercritical Fluids 2010, 55 (1), 223-231. (53) Carrazza, J.; Pereira, P.; Martinez, N. Process and catalyst for upgrading heavy hydrocarbon. Patent US5688395 A, Nov 18, 1997. (54) Duprez, D. Selective steam reforming of aromatic compounds on metal catalysts. Applied Catalysis A: General 1992, 82 (2), 111-157. (55) Pérez Zurita, M. J.; Bartolini, M.; Righi, T.; Vitale, G.; Pereira Almao, P. Hydrotalcite type materials as catalyst precursors for the Catalytic Steam Cracking of toluene. Fuel 2015, 154, 71-79.


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List of Tables: Table 1. Elemental composition of asphaltene precipitated by normal pentane from Athabasca vacuum residue. Table 2. Textural properties of fresh catalyst determined by N2 adsorption at -196.15oC with a Micrometrics Analyzer model TriStar II 3020. *(3wt%NiO-12wt%MoO3)/Alumina. Table 3. Wet oxidation experimental conditions and results including conversion and solubility (the conversions and liquid yields were measured based on carbon content of fractions). *pH was measured at the end of run (Initial pH=12). Table 4. Reaction conditions for hydroprocessing tests on differently prepared SAW. Table 5. Conversion and liquid yield results of hydroprocessing experiments for differently prepared SAW. Table 6. Experimental results of hydroprocessing for different SAW concentrations carried out at 320oC, 3 h, 600psig initial H2 and 0.5 gram NiMoS/Al2O3. Table 7. Effect of catalyst amount on hydroprocessing of concentrated SAW at 320oC, 3 h residence time and 900 psig initial H2 pressure. Table 8. Compounds identified by GC/MS of fresh SAW extracted by CS2 before hydroprocessing experiment (minor fraction of sample). Table 9. Compounds identified by GC/MS of liquid product after hydroprocessing.


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List of Figures: Figure 1. Schematic diagram of proposed asphaltene processing in water. Figure 2. Reaction pathway for asphaltene wet oxidation reaction. Figure 3. Procedure for product separation and analyses for wet oxidation experiments. Figure 4. Schematic of product separation and characterization methods conducted for hydroprocessing experiments. Figure 5. Infrared analysis for A) virgin asphaltene precipitated with pentane B) solubilized asphaltenes in water at 240oC and 2 h residence time before hydroprocessing (SAW II), C) Humic salts (potassium) from Guri dam, Venezuela. Figure 6. Boiling point distribution determined by HTSD analysis for liquid products from hydroprocessing experiments. Figure 7. Products distribution and conversion from HP reaction of SAW at different concentrations. Figure 8. Results of HTSD analyses for hydroprocessing experiments with different concentration levels of SAW. Figure 9. H2 and CO2 distribution in gas phase after hydroprocessing of SAW at different concentration levels. Figure 10. CO and CH4 distribution in gas phase after hydroprocessing of SAW at different concentration levels. Figure 11. Results of product distribution for hydroprocessing of 10X concentrated SAW at 320oC, 3 h residence time and 0.5 gram of catalyst and different hydrogen pressures. Figure 12. Comparison of liquid products boiling point distribution at different hydrogen pressures for hydroprocessing of concentrated SAW solution. Figure 13. Effect of catalyst amount on hydroprocessing of concentrated SAW. Figure 14.TGA results: a) The comparison of weight loss for fresh sulfided catalyst and solids after reaction, b) The mass loss and mass derivatives for fresh sulfided catalyst, c) The detected CO2 and SO2 by mass spectrometry throughout the analyses of fresh sulfided catalyst. Figure 15. TGA results: a) The mass loss and mass derivatives for solid after reaction, b) the detected CO2 and SO2 by mass spectrometry throughout the analyses of solid sample after reaction, c) The comparison of weight loss and weight derivatives for solid sample after reaction with pure asphaltene. Figure 16. Comparison of GC/MS characterization for a) CS2 soluble fraction of fresh SAW and b) liquid product after hydroprocessing of non-concentrated SAW at 320oC, 3h residence time and 600 psig initial H2 pressure.


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Table 1. Elemental composition of asphaltene precipitated by normal pentane from Athabasca vacuum residue. Sample

Carbon wt%

Hydrogen wt%

Nitrogen wt%

Sulfur wt%

C5- Asphaltene

82.5

8.0

0.8

6.5

Table 2. Textural properties of fresh catalyst determined by N2 adsorption at -196.15oC with a Micrometrics Analyzer model TriStar II 3020. *(3wt%NiO-12wt%MoO3)/Alumina. BET surface area(m2/g)

Catalyst 3NiO12MoO3/γ-Al2O3*

Pore

Pore volume (cm3/g)

138

Size(A)

0.36

104

Table 3. Wet oxidation experimental conditions and results including conversion and solubility (the conversions and liquid yields were measured based on carbon content of fractions). *pH was measured at the end of run (Initial pH=12). Product

Temperature ◦

Residence Time

Initial

Solubilized

amount of

Carbon in water

Carbon

after reaction

Carbon Conversion

Liquid Yield (Carbon

pH*

Solubility Level)

C

h

g

g

%

%

SAW I

190

6

3.32

1.59

80

48

7.4

SAW II

215

4

3.33

1.66

69

50

9.0

SAW III

230

3

3.32

1.43

82

43

9.2

SAW VI

240

2

3.33

1.69

83

51

7.7

Denomination


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Table 4. Reaction conditions for hydroprocessing tests on differently prepared SAW. Catalyst amount

SAW amount

g

g

0.5

25

Residence

Hydrogen pressure

Time

at 25oC

C

h

psig

rpm

320

3

600

500

Temperature ◦

Mixing rate

Table 5. Conversion and liquid yield results of hydroprocessing experiments for differently prepared SAW. Oxidation

Oxidation

Hydroprocessing

Hydroprocessing

Temperature

Residence Time

Conversion

Liquid Yield

C

h

%

%

SAW I

190

6

37.5

15

SAW II

215

4

41

15

SAW III

230

3

40.5

15.5

SAW VI

240

2

39

18

Feed

◦

denomination

Table 6. Experimental results of hydroprocessing for different SAW concentrations carried out at 320oC, 3 h, 600psig initial H2 and 0.5 gram NiMoS/Al2O3. Concentrated

Initial amount of C

amount of C in

SAW

in SAW

SAW after reaction

Denomination

mg in 25 milliliters of SAW

No conc.

Conversion

Liquid Yield

Gas Yield

mg in 25 milliliters of SAW

%

%

%

218.2

123.8

40.5

15.5

12.5

2x

465.5

248.6

42.0

12.0

10.5

4x

886.1

497.2

42.5

10.0

9.0

6x

1351.8

814.6

42.0

9.0

8.0

10x

2102.5

1208.2

43.0

9.0

8.0


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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 30 of 42

Table 7. Effect of catalyst amount on hydroprocessing of concentrated SAW at 320oC, 3 h residence time and 900 psig initial H2 pressure. Amount of

Initial amount

Catalyst

of C

g

Conversion

Liquid Yield

Gas Yield

g

%

%

%

0

2.3

29.0

8.0

6.0

0.5

2.34

32.0

12.0

7.0

1

2.34

31.5

11.5

7.5

4

2.32

32.5

12.0

7.0

Table 8. Compounds identified by GC/MS of fresh SAW extracted by CS2 before hydroprocessing experiment (minor fraction of sample). #

Retention

Name

Time(min)

Molecular Formula

Mw

1

7.27

Hexanoic acid

C6H12O2

116.16

2

8.83

Heptanoic acid

C7H14O2

130.18

3

10.19

Octanoic acid

C8H16O2

144.21

4

11.50

Nonanoic acid

C9H18O2

158.24

5

12.63

Decanoic acid

C10H20O2

172.26

6

13.96

Undecanoic acid

C11H22O2

186.29

7

14.73

Dodecanoic acid

C12H24O2

200.32

8

15.11

Tridecanoic acid

C13H26O2

214.34

9

16.21

Pentadecanoic acid

C15H30O2

242.40

10

17.31

Hexaadecanoic acid

C16H32O2

256.42

11

17.79

Octadecanoic acid

C18H36O2

284.48

12

19.28

Nonadecanoic acid

C19H38O2

298.51

13

19.72

Heneicosanoic acid

C21H42O2

326.56

14

20.23

Docosanoic acid

C22H44O2

340.59


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Table 9. Compounds identified by GC/MS of liquid product after hydroprocessing. #

Retention

Name

Time

Molecular Formula

Mw

1

6.87

Phenol

C6H6O

94.11

2

8.18

Naphthalene, decahydro-, trans-

C10H18

138.24

3

8.42

Phenol,3-methyl-

C7H8O

108.13

4

8.75

Naphthalene, decahydro-, cis-

C10H18

138.24

5

9.76

Naphthalene, 1,2,3,4-tetrahydro-

C10H12

132.20

6

10.13

Naphthalene

C10H8

128.17

7

10.24

Benzo[b]thiophene

C8H6S

134.2

8

11.17

Benzo[b]thiophene, 5 methyl

C9H8S

148.25

9

14.43

1-Naphthalenol

C10H8O

144.17

10

15.34

Fluorene

C13H10

166.22


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Page 32 of 42

Figures:

Gas + Solid Products

Virgin Asphalthene

Wet Oxidation In Aqueous Phase

Gas + Sloid Products

Solubilized Asphaltene in Water

Hydroprocessing in Aqueous Phase

Value Added Product

+ H2

+O2

Figure 1. Schematic diagram of proposed asphaltene processing in water.

Figure 2. Reaction pathway for asphaltene wet oxidation reaction.


Page 33 of 42

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

Figure 3. Procedure for product separation and analyses for wet oxidation experiments.

Figure 4. Schematic of product separation and characterization methods conducted for hydroprocessing experiments. 34 ACS Paragon Plus Environment

Energy & Fuels

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Figure 5. Infrared analysis for A) virgin asphaltene precipitated with pentane B) solubilized asphaltenes in water at 240oC and 2 h residence time before hydroprocessing (SAW II), C) Humic salts (potassium) from Guri dam, Venezuela.


Page 34 of 42

Page 35 of 42

800 700 600

Boiling Point (oC)

SAW Preparation Condition

500

SAW II (215oC) SAW III (230oC) SAW IV (240oC)

400 300 200 100 0 0

20

40

60

80

100

120

off(%)

Figure 6. Boiling point distribution determined by HTSD analysis for liquid products from hydroprocessing experiments.

50.0 45.0 40.0

Percentage(%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

35.0 30.0 23.5

25.0

19.5

20.0 15.0

26.0

25.0

12.5

10.0 5.0 0.0 No Conc. Liquid Yield

2X

4X

Gas Yield

6X Solid Yield

10X Conversion

Figure 7. Products distribution and conversion from HP reaction of SAW at different concentrations.


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800 700 Boiling Point (oC)

600

2X

500 4X 400 6X

300

10X

200 100 0 0

20

40

60

80

100

120

Off(%)

Figure 8. Results of HTSD analyses for hydroprocessing experiments with different concentration levels of SAW.

100.00

98.1 97.1 95.3 94.0

90.0

80.00 1X

2X

4X

6X

10X

60.00

mol %

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 36 of 42

40.00

20.00 1.6

2.7

4.3

5.2

9.0

0.00 H2

CO2

Figure 9. H2 and CO2 distribution in gas phase after hydroprocessing of SAW at different concentration levels. 37 ACS Paragon Plus Environment

Page 37 of 42

0.80 1X

0.69

0.70

2X

4X

6X

10X

0.60 0.50

mol %

0.50 0.40

0.33

0.30 0.22 0.18

0.20 0.12 0.08

0.10

0.14

0.10

0.08

0.00 CH4

CO

Figure 10. CO and CH4 distribution in gas phase after hydroprocessing of SAW at different concentration levels.

50.0 45.0 40.0

Percentage(%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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35.0 30.0

26.0

25.0

20.0

20.0 13.0

15.0

13.0 9.5

10.0 5.0 0.0 600 psig

700 psig

Liquid Yield

800 psig

Gas Yield

900 psig

Solid Yield

1000 psig Conversion

Figure 11. Results of product distribution for hydroprocessing of 10X concentrated SAW at 320oC, 3 h residence time and 0.5 gram of catalyst and different hydrogen pressures.


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800 700

Boiling Point(oC)

600 500 700psig

400

1000 psig

300 200 100 0 0

20

40

60

80

100

120

off(%)

Figure 12. Comparison of liquid products boiling point distribution at different hydrogen pressures for hydroprocessing of concentrated SAW solution.

40.0 35.0 30.0

Percentage(%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 38 of 42

25.0 20.0 15.0

15.0

12.5

13.5

1 g Catalyst

4 g Catalyst

13.0

10.0 5.0 0.0 Thermal Liquid Yield

0.5 g Catalyst Gas Yield

Solid Yield

Conversion

Figure 13. Effect of catalyst amount on hydroprocessing of concentrated SAW.


Page 39 of 42

101 99 97

200-700oC 7.21%

Weight(%)

95 93

a)

91 89

o

200-700 C 14.69%

87 85

Solid after Reaction

83

Fresh Sulfided Catalyst

81 0

150

300

450

600

750

900 0.1

0.08

Weight (%)

96 0.06

b) Fresh Sulfided Catalyst

91

0.04 86

0.02

81

Derivate of Weight(%/oC)

101

0 0

150

300

450

600

750

900

c) Fresh Sulfided Catalyst CO2(m/z 44) SO2(m/z 64)

Intensity(E)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

0

150

300

450

600

750

900

Temperature(oC) Figure 14.TGA results: a) The comparison of weight loss for fresh sulfided catalyst and solids after reaction, b) The mass loss and mass derivatives for fresh sulfided catalyst, c) The detected CO2 and SO2 by mass spectrometry throughout the analyses of fresh sulfided catalyst. 40 ACS Paragon Plus Environment

Energy & Fuels

0.1

0.08

96

0.06

a)Solid after reaction

Weight(%)

91

0.04 86

0.02

81


101

0 0

150

300

450

600

750

900

Intensity(E)

CO2(m/z 44) SO2(m/z 64)

b)Solid after reaction

0

150

300

450

600

750

900

Temperature(oC) 1.2

c)

80

1 Solid after reaction W%

60

0.8

Pure Asphaltene W% 0.6

Solid after reaction(dW/dT)

40

Pure Asphaltene(dW/dT)

0.4

20

0.2 0

0 0

150

300

450

600

750


1.4

100

Weight(%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 40 of 42

900

Temperature(oC) Figure 15. TGA results: a) The mass loss and mass derivatives for solid after reaction, b) the detected CO2 and SO2 by mass spectrometry throughout the analyses of solid sample after 41 ACS Paragon Plus Environment

Page 41 of 42

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reaction, c) The comparison of weight loss and weight derivatives for solid sample after reaction with pure asphaltene.

Figure 16. Comparison of GC/MS characterization for a) CS2 soluble fraction of fresh SAW and b) liquid product after hydroprocessing of non-concentrated SAW at 320oC, 3h residence time and 600 psig initial H2 pressure.


Experimental Study on Catalytic Hydroprocessing of Solubilized

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