Effects of Blending and Heat-treating Atmospheric Residues on

Subscriber access provided by UNIV OF ARIZONA

Article

Effects of Blending and Heat-treating Atmospheric Residues on Distribution and Composition of Their SARA Fractions Qingyan Cui, Koji Nakabayashi, Xiaoliang Ma, Jin Miyawaki, Adel AlMutairi, Abdulazim MJ Marafi, Joo-Il Park, Seong-Ho Yoon, and Isao Mochida Energy Fuels, Just Accepted Manuscript • Publication Date (Web): 26 May 2017 Downloaded from http://pubs.acs.org on May 27, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Energy & Fuels is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 32

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

Effects of Blending and Heat-treating on Composition and Distribution of SARA Fractions of Atmospheric Residues Qingyan Cui,a Koji Nakabayashi,a Xiaoliang Ma,b Jin Miyawaki,a Adel Al-Mutairi,b Abdulazim MJ Marafi,b Joo-Il Park,b Seong-Ho Yoon a and Isao Mochida *,c a

Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga,

Fukuoka, Japan b

Petroleum Research Center, Kuwait Institute for Scientific Research, Safat, Kuwait

c

Kyushu Environmental Evaluation Association, Fukuoka, Japan

ABSTRACT: The effects of blending and heat-treating of two atmospheric residues (ARs) from Lower Fars crude and Kuwait export crude on the distribution and composition of their saturate, aromatic, resin and asphaltene (SARA) fractions were studied by using X-ray diffraction (XRD), high temperature gas chromatography equipped with an atomic emission detector (HT-GC-AED), gel permeation chromatography with detection by ultraviolet absorbance (GPC-UV) and inductively coupled plasma mass spectrometry (GPC-ICP-MS), respectively. Although no obvious change in the mass distribution of the SARA fractions is observed, the result from the GPC-ICP-MS analysis shows that blending of the two ARs at room temperature causes the shift of the metal complexes from the asphaltenes to the resins. Heat-treating of the ARs at 330 oC for 3 h under an H2 pressure of 9 MPa changes the mass distribution of the SARA fractions and promotes the shifts of V and Ni complexes in the asphaltenes from the heavy molecular weight to the light molecular weight, and further from the asphaltenes to the resins. The results suggest some potential approaches for improving the hydrodemetallization reactivity of AR by releasing the metals complexes from the

1

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

asphaltenes. 1. INTRODUCTION SARA fractionation, which separates petroleum fractions into saturates, aromatics, resins and asphaltenes, has been used to characterize and explain reaction process and mechanism in the hydrotreating and fluid catalytic cracking (FCC) processes.1-5 The SARA fractionation depends on the solubility of petroleum fractions components in a series of solvents and their interaction with the adsorbent in the column. The solubility of a component is mutually influenced by co-existing components in the phase, thus it is speculated that the composition and distribution of the SARA fractions in petroleum fractions may be modified or changed by mixing with another petroleum fractions and/or heat-treating. Of particular interest are species, such as sulfur (S), nitrogen (N) and metals present mainly in asphaltenes,

6,7

and their shifts between resins and

asphaltenes by changing the dissolution activity of the components in the fractions. The molecular structures of various metal species in petroleum have a significant impact on the reactivity of the metal species in hydrodemetallization (HDM) processes. Metal species in petroleum have been characterized by Fourier transform ion cyclotron resonance mass spectrometry analysis (FT-ICR-MS), and their molecular structures have been proposed based on the assigned elemental formulas.8-10 Concurrently, the environment (matrix) of the metal species also influences their reactivity. Consequently, blending feedstocks may be a way to change the environment of the metal species in petroleum. Hydrodesulfurization (HDS) of a blend from different middle distillates is an example.11-13 The reactivity of various species (S, N and metals) in the SARA fractions may be influenced by their surrounding matrixes. For example, lower conversion rate for asphaltenes in HDS processes is likely due to higher concentrations of the refractory 2


Page 2 of 32

Page 3 of 32

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

S species combined with inhibitorier matrix effects from other asphaltenes components. Hence, a targeted reaction of AR may be improved by the blending and/or pre-heat-treating, which may modify the interaction of sulfur, nitrogen and metal species with their matrixes. In the present study, effects of the blending and heat-treating of two Kuwait ARs (LF-AR and KEC-AR) from Lower Fars crude (LF) and Kuwait export crude (KEC) on distribution and composition of their SARA fractions were examined. The shifts of the S, N and metal species among the fractions were monitored by the SARA fractionations and element analysis of each fraction. The changes in molecular weight distributions of the vanadium (V) and nickel (Ni) complexes in ARs and their fractions were examined by using gel permeation chromatography with an inductively coupled plasma mass spectrometry (GPC-ICP-MS) and high temperature gas chromatography with atomic emission detector (HT-GC-AED). The objective is to clarify whether there are some shifts of the S, N and metal species among the fractions and/or the changes of their interaction with the matrix in the blending and heat-treating processes. Understanding of these phenomena may provide a hint in improving the reactivity of AR in HDM and HDS processes. 2. EXPERIMENTAL SECTION 2.1. AR Samples. LF and KEC, which were provided by Kuwait National Petroleum Company (KNPC), have been distillated in a pilot unit to obtain the LF-AR and KEC-AR with a cutting point at 345

o

C. A blend (LF/KEC-AR) of LF-AR and KEC-AR with a

LF-AR/KEC-AR weight ratio of 1/1 w/w was prepared at room temperature under atmospheric pressure. The densities of LF-AR, KEC-AR and LF/KEC-AR were 1.0018, 3


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

0.9745 and 0.9873 g/mL, respectively. Three heat-treated AR samples (HT-LF-AR, HT-KEC-AR and HT-LF/KEC-AR) were prepared by heat-treating 20 g of LF-AR, KEC-AR and LF/KEC-AR, respectively, at 330 oC under an H2 pressure of 9 MPa with stirring for 3 h in an autoclave. 2.2. SARA Fractionation. About 5 g of the AR sample was dissolved in n-heptane at a ratio of 1/50 (w/w) under stirring at 60 oC for 5 h, and then set overnight at room temperature. The mixture of AR and n-heptane was filtered, and the solid cake was washed with n-heptane until the filtrate was colorless. The insoluble portion was extracted with toluene in a Soxhlet apparatus, and then the solvent in the solution was removed by rotary-evaporating. The received sample was dried at 110 oC for 2 h and weighted to determine the asphaltenes content. The maltene was obtained by rotary-evaporating the n-heptane solution, and then further fractionated into saturates, aromatics and resins through a glass column packed with the activated neutral alumina. Maltene mixed with a small amount of n-hexane was added on the top of the packed column. The column was sequentially eluted with n-heptane, toluene and toluene/methanol (9/1, v/v) at a solvent-to-maltene ratio of 250 mL to 1 g. The respective solutions were rotary-evaporated to obtain saturates, aromatics and resins. 2.3. Characterization of ARs and Their Fractions. X-ray diffraction (XRD) analysis of the sample was carried out using an AXS D8 ADVANCE diffractometer (Bruker, Billerica MA, USA). The Cu Kα radiation (λ= 0.15406 nm at 40 kV, 30 mA) was used, and the scan data was recorded at 20 oC for 2θ in the range from 5 to 80 o in steps of 0.02 o s-1. 4


Page 4 of 32

Page 5 of 32

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

The molecular weight distributions of the ARs and their fractions were determined by gel permeation chromatography (1200 Infinity Series, Agilent Technologies, Santa Clara, CA, USA) with an ultraviolet diode array detector (DAD at 261 nm) (GPC-UV). The approximate molecular size distributions of the metals complexes in them were measured by GPC coupled with an inductively coupled plasma mass spectrometry (7700 series, Agilent) (GPC-ICP-MS) under the plasma condition of 1,600 W RF power and calibrated against

51

V and

60

Ni isotopes. Some V and Ni species from Japan

Petroleum Society were used as standard samples to develop standard calibration curves (R2 > 0.99) for calculation of the concentrations of V and Ni in the samples. The mobile phase was tetrahydrofuran, and the flow rate was 0.15 mL min-1. The ARs, their resins and asphaltenes were diluted by 100, 300 and 500 times of tetrahydrofuran in weight, respectively, and then injected into the GPC-UV and GPC-ICP-MS systems for analysis. High

Temperature

Gas

Chromatography

with

Atomic

Emission

Detector

(HT-GC-AED) analysis was carried out using a gas chromatography (7890; Agilent) coupled with a JAS 2390AA atomic emission detector (Joint Analytical Systems GmbH, Moers, Germany). The gas chromatography was equipped with a 5 m × 0.53 mm × 0.1 µm column and a programmable high-temperature vaporization (PTV) inlet. The oven temperature was programed from 30 to 430 oC at a rate of 30 oC min-1, while the AED transfer line temperature was 430 oC and the cavity temperature was 450 oC. The 292-nm V and 301-nm Ni emission lines were used to detect the AED responses. VOand NiO- octoethyl-etioporphyrins (Sigma-Aldrich, St. Louis, MO, USA) and 5, 10, 15, 20-tetraphenyl porphyrins (Wako Chemicals, Tokyo Japan) were used as metal standard samples. The sample injected into the PTV inlet was dissolved in dichloromethane with 5


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

a concentration of 5 wt %. 3. RESULTS 3.1. Effect of Blending on Distribution and Composition of SARA Fractions. 3.1.1. Content and Composition of SARA Fractions. Table 1a compares the contents of the SARA fractions in single and blended ARs. KEC-AR was significantly lighter than LF-AR in terms of the mass distribution of the SARA fractions, which coincides with their density. The experimental mass recoveries of SARA fractions from the LF/KEC-AR did not deviate from theoretical expectations based on their respective fractions, indicating that no any synergistic effect appeared to take place in the blending at room temperature. Table 2 summarizes the C, H, N and S elemental analyses of ARs and their SARA fractions. As expected, LF-AR showed higher S and N contents and lower H/C ratio compared with KEC-AR. Table 3 summarizes the metals (V and Ni) contents in ARs and their resins and asphaltenes. LF-AR contained significantly more V and Ni than KEC-AR. The concentration of both metals in the asphaltenes is higher than those in the resins for all three ARs. However, the mass distributions of V and Ni in the resins and asphaltenes were similar, except for V in LF-AR, in which the amount of V in the asphaltenes was about 1.5 times of that in the resins. It is interesting to find that when the LF-AR and KEC-AR were mixed, both the V and Ni complexes in the asphaltenes markedly shifted from asphaltenes to the resins by about 12 % for V and 11 % for Ni on the basis of the comparison of the metal amounts (µg/g, based on AR) in the resins and asphaltenes. It indicates clearly that such blending favors the shift of the metals complexes from the asphaltenes to the resins. 3.1.2. XRD of ARs and Their Asphaltenes. 6


Page 6 of 32

Page 7 of 32

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

The XRD profiles of the ARs and their asphaltenes are shown in Figures 1(a) and 2(a), respectively. There were the broad diffraction peaks at about 10 to 30 o, which reflects the contributions of paraffinic and aromatic aggregation. Both LF-AR and KEC-AR had very similar profiles. Two asphaltenes (LF-As and KEC-As) had slightly broader peaks, with stronger diffraction at lower angle about 20 o. A sharper shoulder peak at 26 o for LF-As was clearer than that for KEC-As, which indicates more aromatic stacking in LF-As. The shoulders in LF/KEC-As and KEC-As were similar, suggesting that the blending loosened the aromatic stacking in LF-As somewhat. 3.1.3. GPC-UV and GPC-ICP-MS of ARs, Their Resins and Asphaltenes. Figure 3a shows the GPC-UV chromatograms of ARs, their resins and asphaltenes. The chromatograms of both LF-AR and KEC-AR were very similar. The AR chromatogram consisted of a major peak at 21.0 min and a shoulder at 24.0 min, with a tail at 12.5 to 17.0 min. The resins and asphaltenes showed peaks at about 20.0 min and 18.5 min, respectively, indicating that the average molecular size of the asphaltenes was larger than that of the resins. No obvious difference in the molecular size distribution for the three resins and for the three asphaltenes was observed. Figure 4 shows the GPC-ICP-MS chromatograms of V and Ni complexes in ARs, their resins and asphaltenes. The molecular size distributions of the V and Ni complexes were similar in ARs, resins and asphaltenes from the three crudes, respectively, although their intensities were quite different due to their different metal concentrations. The metal molecular weight distribution can be divided into three groups, i.e., heavy, medium and light, which corresponded to retention times of less than 17.0 min (from 12.0 min), 17.0 to 20.0 min, and more than 20.0 min (to 24.0 min), respectively, as indicated in Figure 4. The first two groups were dominantly present in asphaltenes, 7


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

while the latter group was present in both asphaltenes and resins. The blending of two ARs changed the distribution of the V complexes in asphaltenes, modifying the intensity of the medium and light groups to close to those of KEC-AR. There was a definite increase in the intensity of the V complexes in the resins and a definite decrease in the intensity of the V complexes in the asphaltenes, especially for the medium and light groups of LF/KEC-As, indicating that the blending appeared to shift the metal complexes from the asphaltenes to the resins. It is in agreement with the results shown in Table 3. Distribution of the Ni complexes in the three groups was basically the same as that of the V complexes, although the intensity of Ni complexes was significantly weaker than that of V complexes. The effect of blending on the distribution of Ni complexes was also similar to that of the V complexes. 3.1.4. HT-GC-AED of ARs, Their Resins and Asphaltenes. The HT-GC-AED chromatograms of ARs, their resins and asphaltenes are illustrated in Figure 5a for V and 5b for Ni. The V species in AR were broadly distributed in terms of their retention times, i.e., from 9.0 to longer than 13.0 min. The obtained peaks can be classified into two major groups, from 9.0 to 9.7 min and from 9.7 to 10.5 min, respectively. The octoethyl-etioporphyrin VO (Octoethyl-etio-VO) should be included in the first group at about 9.5 min, while the tetraphenyl porphyrin V (TPP-V) appears at about 10.8 min on the basis of their retention times measured by using the standard samples. It indicates that the major V species in the second group were slightly lighter than TPP-V. The relative intensity of the first group to the second group for both LF/KEC-AR and LF/KEC-R was slightly higher than that of LF-AR and LF-R, and similar to that of KEC-AR and KEC-R, indicating somewhat decrease in the molecular weight of the V species in the blending. This is consistent with the observation by the 8


Page 8 of 32

Page 9 of 32

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

GPC-ICP-MS analysis. The Ni species detected by HT-GC-AED were located in the same retention time region as that of the V species, but much sharper peaks were observed for Ni species in the first group having retention times from 9.0 to 10.5 min, and the second group from 10.5 to 11.5 min. The distributions of each group in the resins and the asphaltenes were different, and the second group was dominantly present in the asphaltenes. The effect of blending on the Ni species distribution was indefinite in this case. 3.2. Effect of Heat-treating on Distribution and Composition of SARA Fractions. 3.2.1. SARA Fractions Contents of Heat-treated ARs. Table 1b summarizes the SARA fraction contents of ARs after the heat-treating at 330 o

C under an H2 pressure of 9 MPa for 3 h. This condition was selected as it may be the

highest temperature that can be used without coke formation. When the heat-treating was carried out below 330 oC, no significant change in the SARA fractions contents of the heat-treated ARs was observed. The heat-treating at 330 oC substantially increased the content of the resins, and decreased the content of the aromatics for all three ARs. It indicates that the heat-treating of ARs, even under an H2 pressure of 9 MPa, enhanced the coupling of aromatics components, and shifted them mainly into the resins. Interestingly, it was found that the blending of ARs moderated such coupling of aromatics components, and enhanced the disassociation of the resins and asphaltenes in the heat treatment. This resulted in a decrease of percentages of the resins and asphaltenes, but an increase of percentage of the aromatics on the basis of the comparison of experimental data with those (shown in parentheses in Table 1b) expected by linear mixing two single ARs after the heat treatment. 3.2.2. XRD of Heat-treated ARs and Their Asphaltenes. 9


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

No significant difference was observed in the XRD profiles of ARs after the heat-treating at 330 oC (Figure 1b). In contrast, the peak at 26 o for the asphaltenes from the three ARs appeared to slightly intensify after the heat treatment, as indicated by comparison of Figures 2a and 2b. It implies that the somewhat enhancement in the aromatic stacking and/or phase separation from the three ARs were observed after the heat treatment. 3.2.3. GPC-UV and GPC-ICP-MS of Heat-treated ARs, Their Resins and Asphaltenes. Figure 3b illustrates the GPC-UV chromatograms of the heat-treated ARs and their resins and asphaltenes. The heat-treating removed the tails at 12.5 to 17.0 min for the three ARs, and significantly shifted the peak at around 18.5 min to around 20.0 min for the asphaltenes. The peak of HT-LF/KEC-As appeared to be shifted more to longer elution times in comparison with those of the HT-LF-As and HT-KEC-As, indicating a reduction of molecular weight after the blending and heat-treating. The GPC-ICP-MS chromatograms of the V and Ni complexes in ARs and their resins and asphaltenes after the heat-treating at 330 oC are shown in Figure 6. In comparison of Figures 4 and 6, marked change induced by the heat-treating was observed. The two top peaks in the AR and asphaltenes at 21.0 and 16.5 min were shifted to 22.7 and 23.0 min, respectively. The relative intensities of the peaks also changed, such that the intensities of the peaks at longer elution time for all three asphaltenes were greatly enhanced. The mixed and single ARs had similar peak profiles, and the peak intensity of the resins (HT-LF/KEC-R) from the heat-treated LF/KEC-AR was almost the same as that of the resins (HT-LF-R) from the heat-treated LF-AR, and the peak intensity of the asphaltenes (HT-LF/KEC-As) from the heat-treated LF/KEC-AR was similar to those of the asphaltenes (HT-KEC-As) from the heat-treated KEC-AR. This indicates that the 10


Page 10 of 32

Page 11 of 32

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

heat-treating caused a shift of the metal complexes from the asphaltenes to the resins in the blending. Additionally, the medium and heavy groups of V complexes in HT-LF/KEC-AR and HT-LF/KEC-As were eluted similarly to those of HT-KEC-AR and HT-KEC-As, which suggests that the heat-treating and blending reduced the amount of the heavy V complexes, possibly due to dissociation of the V complexes from their organic compound matrixes. Table 4 summarizes the metals contents of the heat-treated ARs, their resins and asphaltenes. The content of the V complexes (68 µg/g) in HT-LF-R was higher than that in LF-R (59 µg/g), indicating that the heat-treating caused a shift of the V complexes from the asphaltenes to the resins by increasing about 15.2 % of the V complexes in the resin for LF-AR. However, such increase in the shift of the V complexes for KEC-AR was limited (< 3%), indicating that the positive effect of the heat-treating may be more significant for the heavy AR. Interestingly, the heat-treating of LF/KEC-AR enhanced the shift of the metals complexes from the asphaltenes to the resins more significantly, increasing the shift by 15.7 %for V and 20 % for Ni, implying that the heat-treating is more effective in promoting the metal shifts for the blended AR. 3.2.4. HT-GC-AED of Heat-treated ARs, Their Resins and Asphaltenes. Figure 7 shows the HT-GC-AED chromatograms of the V and Ni species in the heat-treated ARs, their resins and asphaltenes. In comparison with Figure 5, the peaks corresponding to the V and Ni species in the heat-treated ARs shifted to the light part, and the peaks in the heavy part for both V and Ni species were significantly reduced in AR, resins and asphaltenes. It is clear that the heat-treating caused the shift of both V and Ni species from the high to the low retention time region, indicating a decrease in the molecular weight of the metal species, which is consistent with the findings in 3.2.3 11


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

section. 4. DISCUSSION 4.1. Shift of Metals Complexes in ARs Fractions by Blending. The presence of the metals complexes in petroleum has been studied extensively,14-17 since Yen and his group18-22 proposed their trapped model for asphaltene aggregation. The metals complexes have been found mainly in the resins and asphaltenes. Series Etio-VO and deoxophylloerythroetio porphyrins (DPEP) are common metal species in petroleum, and series tetraphenyl porphyrins have been identified,16, 23-26 In addition, other tetradentate ligands and a variety of pendants on the metal core ligands have been reported.17,21 The metals complexes are present in the fractions of organic compounds having similar physical and chemical properties, such as boiling point, polarity and solubility, where the physical and chemical interactions of the metal complexes with the organic components matrixes can trap the metal complexes through non-covalent, coordinative and physical bonding. Coordinative bonding can form through the pendants and axial coordination.17, 27 Molecular interactions, such as strong Van der Waals’ force between molecules, π–π stacking of aromatic planes and the hydrogen bonding between polar groups, have also been postulated between the metal complexes and the organic compounds in petroleum and asphaltenes. Some solvents can extract the metal complexes from the petroleum or its fractions by breaking down such interactions.18, 28 The environment of the metal complexes presented in the AR and its fractions can be changed by blending different ARs, as found in the present study that the blending of LF-AR and KEC-AR shifts a part of metal complexes from the asphaltenes to the resins. More than half amount of the metal complexes in the asphaltenes is present in the heavy 12


Page 12 of 32

Page 13 of 32

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

and medium sub-fractions, as shown in Figure 4. The blending of two ARs causes the shift of a part of metal complexes in the heavier sub-fraction to the lighter one in the asphaltenes, and a part of the medium and light asphaltenes sub-fractions to the resins. In the blending, the aromatics and resins from KEC-AR may act as solvents toward the asphaltenes and contaminated LF-AR, and thus benefit such shift. 4.2. Effect of Heat-treating on Compositions of SARA Fractions. Hydrovisbreaking is a heat-treating process in petroleum refining to reduce the viscosity of heavy petroleum through thermal modification with limited cracking or coking.29-31 The present study selects a temperature of 330 °C under an H2 pressure of 9 MPa for 3 h, as the heat-treating below this temperature shows almost no change in the SARA contents, while the heat-treating higher than this temperature causes significant coking. The present results show that the heat-treating at this condition changes the fractional compositions of the ARs. A significant increase in the resins content is noticed, which is compensated by a decrease of the aromatics content. The observed changes in fractional composition and distribution indicate that somewhat non-covalent bonds among the component molecules are broken down. The heat-treating shifts the metal complexes among the fractions in the single ARs, increasing the content of metal complexes in the resins, but decreasing the content of metal complexes in the asphaltenes. This could be ascribed to the modification of non-covalent bond between the metal complexes and the co-existing organic components in the fractions. The heat-treating at 330 oC further enhances the effect of blending on the shift of the metal complexes from the heavy and medium sub-fractions to the light sub-fraction of asphaltenes, and further from the asphaltenes to the resins, which can be attributed to the enhancement of solvating power of the matrix and the improvement of solubility of 13


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

Page 14 of 32

the metal complexes in ARs by the heat-treating. The compositional change in the aromatics and resins, which are functioned as solvent, can change the environment of the metal complexes and finally causes the shift of the metal complexes. Such shift of the metal complexes from asphaltenes to resins should be favorable to the metal removal in the hydrodemetallization process. Future studies would be suggested to explore how to enhance the metal complexes shift by a pretreatment before the hydrodemetallization. 4.3. Aromatic Stacking in Asphaltenes. The aromatic π–π stacking in the asphaltenes results in a diffraction peak at 26 o, as shown in Figure 2. The intensity of this peak is affected by the heat-treating. The antisolvent effects of the heat-treating on the formation of aromatic planes from the non-aromatic components and phase separation are suspected to form the more rigid asphaltenes, which is more difficult to be hydrotreated. Such refractory asphaltenes, if present, must be considered in developing a more effective hydrotreating process for deep refining. 4.4. State of Metal Complexes in the Resins and Asphaltenes. The present study confirms further that the metal complexes are present principally in both resins and asphaltenes. The metal complexes have been analyzed and reported previously by using GPC-ICP-MS and HT-GC-AED.

7, 32-34

GC separates the

compounds on the basis of their interaction with the column and the thermal vaporization, while GPC separation depends on the packing pore in column and the molecule size of the compounds. The GPC-ICP result reveals that the metal complexes are eluted together with the co-existing organic compounds in AR, its resins and asphaltenes, because the molecule sizes of the metal complexes are similar to that of the 14


Page 15 of 32

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

organic compounds, when they are soluble in the elution solvent. In the GC analysis, the metal complexes and the organic compounds of matrixes in the resins and asphaltenes are shot together into the vaporizing element of the GC, and vaporized according to their relative vapor pressures of the molecules in a gas flow. The metal complexes with high vapor pressure are vaporized separately from the high boiling components of the organic matrix, and are eluted separately in the column. On the basis of above understanding, it appears that the metal complexes presented in the resins and asphaltenes have similar properties and/or boiling points to their matrixes comprised of organic compounds. Weak bonds between the metal complexes and their matrixes can be thermally broken at high temperature to liberate the metal complexes from the matrix to some extent. The result suggests several potential approaches for enhancing the hydrodemetallization performance of AR through liberation of the metal complexes from the asphaltenes matrix. The dissolution or solvation of the asphaltenes in the additive solvent component is favorable to promoting the liberation of the metal complexes in the matrixes. Additionally, thermal and chemical cracking of the weak bonds between the metal complexes and the asphaltenes also assists the liberation. 5. CONCLUSIONS The present results show that there is a strong interaction between the V and Ni complexes with their matrixes in ARs and their fractions. Blending of the two ARs at room temperature is beneficial to the shift of the metal complexes from the asphaltenes to the resins, although almost no obvious change in the content distribution of the SARA fractions. The heat-treating of the ARs at 330 oC for 3 h under an H2 pressure of 9 MPa changes both the distribution of SARA fractions. Meanwhile, the heat-treating promotes the shift of the metal complexes in the asphaltenes from the large molecular 15


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

size part to the small molecular size part, and further from the asphaltene to the resins. The results suggest some potential approaches for improving the hydrodemetallization reactivity of AR through the methods, such as the blending and/or the pre-heat-treating, to promote the release of the metals complexes from the asphaltenes. AUTHOR INFORMATION Corresponding Author *E-mail: [email protected]; Tel: (081) 092-662-0410. ACKNOWLEDGMENTS The authors acknowledge the Japan Cooperation Center Petroleum (JCCP), the Kuwait Oil Company (KOC) and the Kuwait Institute for Scientific Research (KISR) for supporting on this joint project. Acknowledgment is also extended to the Kuwait National Petroleum Company (KNPC) for the in-kind contribution and technical support. REFERENCES (1) Leyva, C.; Rana, M. S.; Trejo, F.; Ancheyta, J. On the use of acid-base-supported catalysts for hydroprocessing of heavy petroleum. Ind. Eng. Chem. Res. 2007, 46, 7448–7466. (2) Sahu, R.; Song, B. J.; Jeon, Y. P.; Lee, C. W. Upgrading of vacuum residue in batch type reactor using Ni-Mo supported on goethite catalyst. Journal of Industrial and Engineering Chemistry 2016, 35, 115–122. (3) Gaspar, A.; Zellermann, E.; Lababidi, S.; Reece, J.; Schrader, W. Characterization of saturates, aromatics, resins, and asphaltenes heavy crude oil fractions by atmospheric pressure laser ionization Fourier transform ion cyclotron resonance mass spectrometry. Energy Fuels 2012, 26, 3481–3487. 16


Page 16 of 32

Page 17 of 32

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

(4) Park, J.; Al-Mutairi, A.; Marafi, A.; Yoon, S. H.; Mochida, I.; Ma, X. L. Analysis of vanadium and nickel species in typical Kuwait atmospheric residues using both gel permeation chromatography coupled with ICP-MS and high temperature gas chromatography coupled with atomic emission detector. Journal of Industrial and Engineering Chemistry 2016, 34, 204–212. (5) Park, J.; Al-Mutairi, A.; Marafi, A.; Mochida, I.; Yoon, S. H.; Ma, X. L. Behaviors of metal compounds during hydrodemetallization of atmospheric residue. Journal of Industrial and Engineering Chemistry 2016, 40, 34–39. (6) Bartholdy, J.; Andersen, S. I. Changes in asphaltene stability during hydrotreating. Energy Fuels 2000, 14, 52–55. (7) Barbier, J.; Marques, J.; Caumette, G.; Merdrignac, I. Monitoring the behaviour and fate of nickel and vanadium complexes during vacuum residue hydrotreatment and fraction separation. Fuel Process. Technol. 2014, 119, 185–189. (8) Rodgers, R. P.; Hendrickson, C. L.; Emmett, M. R. Molecular characterization of petroporphyrins in crude oil by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Canadian Journal of Chemistry 2001, 79, 546–551. (9) Zhao, X.; Liu, Y.; Xu, C. M.; Yan, Y. Y.; Zhang, Y. H.; Separation and characterization of vanadyl porphyrins in Venezuela Orinoco heavy crude oil. Energy Fuels 2013, 27, 2874–2882. (10) Liu, H.; Mu, J.; Wang, Z. X.; Ji, S. F.; Shi, Q. Characterization of vanadyl and nickel porphyrins enriched from heavy residues by positive-ion electrospray ionization FT-ICR mass spectrometry. Energy Fuels 2015, 29, 4803–4813. (11) Eng, O. T. Integrated hydrotreating process for the dual production of FCC treated feed and an ultra low sulfur diesel stream. US Patent 6843906. 2005. 17


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

(12) Chen, N. Y. Catalytic hydroconversion of residual stocks. US Patent 4302323. 1981. (13) Shafi, R.; Hamad, E. Z.; Kresman, S. C.; Alzaid, A. H. Process for the treatment of heavy oils using light hydrocarbon components as a diluent. US Patent 4302323. 2009. (14) Miller, J. T.; R. B. Fisher. Structural determination by XAFS spectroscopy of non-porphyrin nickel and vanadium in Maya residuum, hydrocracked residuum, and toluene-insoluble solid. Energy Fuels 1999, 13, 719–727. (15) Xu, H.; Yu, D. Y.; Que, G. H. Characterization of petroporphyrins in Gudao residue by ultraviolet-visible spectrophotometry and laser desorption ionization-time of flight mass spectrometry. Fuel 2005, 84, 647–652. (16) Doukkali, A.; Saoiabi, A.; Zrineh, A.; Hamad, M.; Barbe, J. M.; Guilard, R. Separation and identification of petroporphyrins extracted from the oil shales of Tarfaya: Geochemical study. Fuel 2002, 81, 467–472. (17) Dechaine, G. P.; Gray, M. R. Chemistry and association of vanadium compounds in heavy oil and bitumen, and implications for their selective removal. Energy Fuels 2010, 24, 2795–2808. (18) Tynan, E.; Yen, T .F. Association of vanadium chelates in petroleum asphaltene as studied by ESR. Fuel 1969, 43, 191–208. (19) Yen, T. F.; Erdman, J. G.; Pollack, S. S. Investigation of the structure of petroleum asphaltenes by X-Ray diffraction. Analytical Chemistry 1961, 33, 1587–1594. (20) Dickie, J. P.; Yen, T. F. Macrostructures of the asphaltic fractions by various instrumental methods. Analytical Chemistry 1967, 39, 1847–1852. (21) Vaughan, G. B.; Tynan, E. C.; Yen, T. F. Vanadium complexes and porphyrins in asphaltene, 2. The nature of highly aromatic substituted porphyrins and their vanadyl 18


Page 18 of 32

Page 19 of 32

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

chelates. Chemical Geology 1970, 6, 203–219. (22) Barakat, A. O.; Yen, T. F. Nature of porphyrins in kerogen. Evidence of entrapped etioporphyrin species. Energy Fuels 1989, 3, 613–616. (23) Pena, M. E.; Manjarrez, A.; Campero, A.; Distribution of vanadyl porphyrins in a Mexican offshore heavy crude oil. Fuel Processing Technology 1996, 46, 171–182. (24) Qian, K.; Mennito, A. S.; Edwards, K. E.; Ferrughelli, D. T. Observation of vanadyl porphyrins and sulfur-containing vanadyl porphyrins in a petroleum asphaltene by atmospheric pressure photonionization Fourier transform ion cyclotron resonance mass spectrometry. Rapid Commun. Mass Spectrom. 2008, 22, 2153–2160.

(25) Vaughan, G. B.; Tynan, E. C.; Yen, T. F. Vanadium complexes and porphyrins in asphaltene, 2. The nature of highly aromatic substituted porphyrins and their vanadyl chelates. Chemical Geology 1970, 6, 203–219. (26) Fish, R. H.; Komlenic, J. J.; Wines, B. K. Characterization and comparison of vanadyl and nickel compounds in heavy crude petroleums and asphaltenes by reverse-phase and size-exclusion liquid chromatography/graphite furnace atomic absorption spectrometry. Anal. Chem. 1984, 56, 2452–2460. (27) Bencosme, C. S; Romero, C.; Simoni, S. Axial interaction of vanadyl tetraphenylporphyrin with Lewis bases. Inorg. Chem. 1985, 24, 1603–1604. (28) Akbarzadeh, K.; Dhillon, A.; Svrcek, W. Y.; Yarranton, H. W. Methodology for the characterization and modeling of asphaltene precipitation from heavy oils diluted with n-alkanes. Energy Fuels 2004, 18, 1434–1441. (29) Menoufy, M. F.; Ahmed, H. S.; Betiha, M. A.; Sayed, M. A. A comparative study on hydrocracking and hydrovisbreaking combination for heavy vacuum residue 19


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

conversion. Fuel 2014, 119, 106–110. (30) Thomas, M.; Fixari, B.; Perchec, P. L.; Princic, Y.; Lena, L. Visbreaking of Safaniya vacuum residue in the presence of additives. Fuel 1989, 68, 318–322. (31) Speight, J. G. New approaches to hydroprocessing. Catalysis Today 2004, 98, 55– 60. (32) Desprez, A.; Bouyssiere, B.; Arnaudguilhem, C.; Krier, G.; Vernex-Loset, L. Study of the size distribution of sulfur, vanadium, and nickel compounds in four crude oils and their distillation cuts by gel permeation chromatography inductively coupled plasma high-resolution mass spectrometry. Energy Fuels 2014, 28, 3730–3737. (33) Acevedo, S.; Guzman, K.; Labrador, H.; Carrier, H.; Bouyssiere, B.; Trapping of metallic porphyrins by asphaltene aggregates: A size exclusion Microchromatography with high-resolution inductively coupled plasma mass spectrometric detection study. Energy Fuels 2012, 26, 4968–4977. (34) Kim, T.; Ryu, J.; Kim, M. J.; Shul, Y. G.; Jeon, Y.; Park, Jl. Characterization and analysis of vanadium and nickel species in atmospheric residues. Fuel 2014, 117, 783– 791.

20


Page 20 of 32

Page 21 of 32

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

TABLE CAPTIONS Table 1. SARA contents of single and mixed ARs. (a) Without heat-treatment. (b) With heat-treatment. Table 2. Chemical analyses of ARs and their SARA fractions by element analyses and XRF. Table 3. V and Ni contents of ARs, their resins and asphaltenes by GPC-ICP-MS. Table 4. V and Ni contents of heat-treated ARs, their resins and asphaltenes by GPC-ICP-MS.

21


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 CAPTIONS Figure 1. XRD patterns of (a) ARs and (b) heat-treated ARs. Figure 2. XRD patterns of the asphaltene fraction of (a) ARs. (b) heat-treated ARs. Figure 3. GPC chromatograms of ARs, their resins and asphaltenes. (a) ARs, their resins and asphaltenes. (b) Heat-treated ARs, their resins and asphaltenes. Figure 4. GPC-ICP-MS chromatograms of ARs, their resins and asphaltenes. (a) V species. (b) Ni species. Figure 5. HT-GC-AED chromatograms of ARs, their resins and asphaltenes. (a) V species. (b) Ni species. Figure 6. GPC-ICP-MS chromatograms of heat-treated ARs, their resins and asphaltenes. (a) V species. (b) Ni species. Figure 7. HT-GC-AED chromatograms of heat-treated ARs, their resins and asphaltenes. (a) V species. (b) Ni species.

22


Page 22 of 32

Page 23 of 32

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

TABLES Table 1. SARA Contents of Single and Mixed ARs. (a) Without Heat-treating. Fractions contents

LF-AR

LF/KEC-AR

KEC-AR

Saturates, wt %

16.7±0.3

20.7±0.4 (21.2)

25.7±0.4

Aromatics, wt %

51.9±0.7

50.2±0.6 (50.4)

48.8±0.4

Resins, wt %

19.5±0.4

19.2±0.2 (18.9)

18.4±0.3

Asphaltenes, wt %

11.9±0.2

9.9±0.3 (9.6)

7.2±0.2

Total recovery, wt %

96.7±1.1

97.8±1.5

97.4±1.0

(b) With Heat-treating. Fractions contents

HT-LF-AR

HT-LF/KEC-AR

HT-KEC-AR

Saturates, wt %

16.7±0.2

21.7±0.4 (20.4)

24.2±0.3

Aromatics, wt %

45.3±0.5

47.0±0.4 (44.7)

44.1±0.5

Resins, wt %

25.7±0.3

21.4±0.2 (24.2)

22.7±0.4

Asphaltenes, wt %

12.3±0.1

9.8±0.2 (10.7)

9.1±0.2

Total recovery, wt %

98.2±1.3

96.3±1.0

97.7±1.1

Data in parentheses: theoretical value

23


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

Page 24 of 32

Table 2. Chemical Analyses of ARs and Their SARA Fractions by Element Analyses and XRF. C wt %

H wt %

N wt %

S wt %

H/C atomic ratio

Ash mg/g

LF-AR LF/KEC -AR

82.6

10.1

0.33

3.44

1.46

0.0

83.4

10.5

0.32

3.34

1.51

0.0

KEC-AR

83.8

11.0

0.29

3.19

1.56

0.0

LF-AR LF/KEC -AR

86.3

13.6

0.0

0.15

1.89

0.0

86.0

13.8

0.03(0.0)

0.21 (0.19)

1.93

0.0

KEC-AR

86.2

13.8

0.0

0.23

1.93

0.0

LF-AR LF/KEC -AR

82.6

10.0

0.05

2.37

1.46

0.0

82.8

10.3

0.12(0.06)

3.26(2.97)

1.49

0.0

KEC-AR

84.0

11.0

0.07

3.56

1.53

0.0

LF-AR LF/KEC -AR

80.1

8.7

0.83

4.40

1.30

0.0

81.0

9.1

0.89(0.78)

4.68(4.47)

1.35

0.0

KEC-AR

81.2

9.3

0.73

4.53

1.38

0.0

LF-AR LF/KEC -AR

80.5

7.3

1.01

6.78

1.09

2.5

81.1

7.5

0.90(0.95)

6.12(6.69)

1.11

0.5

KEC-AR

81.9

7.5

0.89

6.59

1.10

1.3

Samples

ARs

Saturates

Aromatics

Resins

Asphaltenes

Data in parentheses: theoretical value Standard error: ± 0.5 %

24


Page 25 of 32

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

Table 3. V and Ni Contents of ARs, Their Resins and Asphaltenes by GPC-ICP-MS. Samples

LF

LF/KEC

KEC

AR

Resins

Asphaltenes

Percent in AR, wt %

---

19.5

11.9

V, ppm

152±1.5

303±1.3

765±1.9

µg/1g base of AR

152

59

91

Ni, ppm

24±0.9

62±0.8

113±1.1

µg/1g base of AR Percent in AR, wt %

24

12

13

---

19.2

9.9

V, ppm

108±1.2 (111)

273±1.4 (245)

587±1.5 (649)

µg/1g base of AR

108

52 (46)

58 (65)

µg/1g moved

---

6

7

Ni, ppm

20±0.6 (19)

52±0.7 (46)

91±0.9 (108)

µg/1g base of AR

20

10 (9)

9 (10)

µg/1g moved Percent in AR, wt %

---

1

1

---

18.4

7.2

V, ppm

71±1.1

187±0.9

533±1.2

µg/1g base of AR

71

34

38

Ni, ppm

14±0.7

31±0.8

103±0.9

µg/1g base of AR

14

6

7


25


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

Page 26 of 32

Table 4. V and Ni Contents of Heat-treated ARs, Their Resins and Asphaltenes by GPC-ICP-MS. Samples

ARs

Percent in AR, wt % HT-LF

HT-LF/KEC

HT-KEC

---

Resins

Asphaltenes

25.7

12.3

V, ppm

151±1.2

264±1.5

653±1.4

µg/1g base of AR

151

68

80

Ni, ppm

26±0.8

55±1.1

107±1.2

µg/1g base of AR Percent in AR, wt %

26

14

13

---

21.4

9.8

V, ppm

111±1.4 (113)

278±1.2 (210)

509±1.0 (535)

µg/1g base of AR

111

60 (52)

50 (59)

8

9

µg/1g moved Ni, ppm

19±0.7 (20)

58±0.5 (43)

79±0.9(91)

µg/1g base of AR

19

12 (10)

8 (10)

µg/1g moved Percent in AR, wt %

---

2

2

---

22.7

9.1

V, ppm

74±1.2

155±0.9

416±1.1

µg/1g base of AR

74

35

38

Ni, ppm

13±0.5

31±0.7

75±1.0

µg/1g base of AR

13

7

7


26


Page 27 of 32

FIGURES HT-LF-AR HT-KEC-AR HT-LF/KEC-AR Intensity(a.u.)

Intensity (a.u.)

LF-AR KEC-AR LF/KEC-AR

20

40 2 Theta

60

80

20

(a)

40 2 Theta

60

80

(b)

Figure 1. XRD patterns of (a) ARs and (b) heat-treated ARs. HT-LF-As HT-KEC-As HT-LF/KEC-As Intensity (a.u.)

LF-As KEC-As LF/KEC-As Intensity (a.u.)

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

20

40 2 Theta

60

80

20

(a)

40 2 Theta

60

80

(b)

Figure 2. XRD patterns of the asphaltenes of (a) ARs and (b) heat-treated ARs.

27


Energy & Fuels

Intensity (a.u.)

360

400


LF-R KEC-R LF/KEC-R

320 Intensity (a.u.)

450

270 180

240 160 80

90

0

0 10

15 20 Elution time (min)

25

30

10


25

30

25

30

250 LF-As KEC-As LF/KEC-As

Intensity (a.u.)

200 150 100 50 0

10


25

30

(a) ARs, their resins and asphaltenes.

360

400

HT-LF-AR HT-KEC-AR HT-LF/KEC-AR

HT-LF-R HT-KEC-R HT-LF/KEC-R

320 Intensity(a.u.)

450

270 180

240 160 80

90

0

0 10


25

250 200 Intensity(a.u.)

Intensity(a.u.)

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 28 of 32

30

10


HT-LF-As HT-KEC-As HT-LF/KEC-As

150 100 50 0 10


25

30

(b) Heat-treated ARs, their resins and asphaltenes. Figure 3. GPC-UV chromatograms of ARs, their resins and asphaltenes.

28


Page 29 of 32

Intensity(cps)

2000


3000 1

2

3

LF-R KEC-R LF/KEC-R

2400 Intensity(cps)

2500

1500 1000

1

2

3

1800 1200 600

500

0

0 10


25

3000

Intensity(cps)

30

10

LF-As KEC-As LF/KEC-As

2400

1

2


25

30

25

30

3

1800 1200 600 0 10


25

30

(a) V species.

800

LF-AR KEC-AR LF/KEC-AR 1

1000

2

LF-R KEC-R LF/KEC-R

800

3

1

2

3

Intensity(cps)

1000

Intensity(cps)

600

600

400

400

200

200

0

0 10


25

30

10


1200

900 Intensity(cps)

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


1

2

3

600

300

0 10


25

30

(b) Ni species. Figure 4. GPC-ICP-MS chromatograms of ARs, their resins and asphaltenes.

29


10 11 Retention time (min)

AED response (a.u.)

9

TPP-VO

Page 30 of 32

LF-R KEC-R LF/KEC-R Octoethyl-etio-VO

AED response(a.u.)

LF-AR KEC-AR LF/KEC-AR Octoethyl-etio-VO

8

12

13

8

9

12

13

TPP-VO


12

13

12

13

LF-As KEC-As LF/KEC-As Octoethyl-etio-VO TPP-VO

8

9


(a) V species. LF-AR KEC-AR LF/KEC-AR Octoethyl-etio-NiO

8

9

LF-R KEC-R LF/KEC-R

AED response(a.u.)

AED response(a.u.)

TPP-NiO


12

13

Octoethyl-etio-NiO

8

9

12

13

TPP-NiO



AED response(a.u.)

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

AED response(a.u.)

Energy & Fuels

Octoethyl-etio-NiO

8

9

TPP-NiO


(b) Ni species. Figure 5. HT-GC-AED chromatograms of ARs, their resins and asphaltenes.

30


Page 31 of 32

3000

2500

HT-LF-AR HT-KEC-AR HT-LF/KEC-AR 3 1 2

HT-LF-R HT-KEC-R HT-LF/KEC-R 2 1 3

2000 Intensity(cps)

Intensity (cps)

2400 1800 1200

1500 1000 500

600

0

0 10


25

30

10

15 20 Elution time(min)

25

30

25

30

3000 HT-LF-As HT-KEC-As HT-LF/KEC-As 2 3 1

Intensity(cps)

2400 1800 1200 600 0

10


25

30

(a) V species.

900

1200

HT-LF-AR HT-KEC-AR HT-LF/KEC-AR 3 1 2

HT-LF-R HT-LF/KEC-R

HT-KEC-R 1

2

3

900 Intensity (cps)

1200

600

300

600

300

0

0 10


25

30

10


1500 1200 Intensity(cps)

Intensity(cps)

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

HT-LF-As HT-KEC-As HT-LF/KEC-As 2 1 3

900 600 300 0 10


25

30

(b) Ni species. Figure 6. GPC-ICP-MS chromatograms of heat-treated ARs, their resins and asphaltenes. 31



AED response(a.u.)

9

AED response(a.u.)

HT-LF-AR HT-KEC-AR HT-LF/KEC-AR Octoethyl-etio-VO TPP-VO

8

12

13

Page 32 of 32

HT-LF-R HT-KEC-R HT-LF/KEC-R Octoethyl-etio-VO TPP-VO

8

9

12

13


12

13

12

13

HT-LF-As HT-KEC-As HT-LF/KEC-As Octoethyl-etio-VO TPP-VO

8

9


(a) V species.

8

9

TPP-NiO


AED response(a.u.)

HT-LF-AR HT-KEC-AR HT-LF/KEC-AR Octoethyl-etio-NiO

AED response(a.u.)

AED response (a.u.)

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

AED response(a.u.)

Energy & Fuels

12

13

HT-LF-As HT-KEC-As HT-LF/KEC-As Octoethyl-etio-NiO

8

9

HT-LF-R HT-KEC-R HT-LF/KEC-R Octoethyl-etio-NiO

8

9

12

13

TPP-NiO


TPP-NiO


(b) Ni species. Figure 7. HT-GC-AED chromatograms of heat-treated ARs, their resins and asphaltenes. 32


Effects of Blending and Heat-treating Atmospheric Residues on

Recommend Documents