Determination and Understanding of Solvent Losses to Tailings from a

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Determination and Understanding of Solvent Losses to Tailings from a Hybrid Bitumen Extraction Process Feng Lin, Yuming Xu, and Richard Nelson Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.8b01978 • Publication Date (Web): 28 Aug 2018 Downloaded from http://pubs.acs.org on August 28, 2018

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Determination and Understanding of Solvent Losses to Tailings from a Hybrid Bitumen Extraction Process ,

Feng Lin,* † Yuming Xu,† Richard Nelson‡ †Natural Resources Canada, CanmetENERGY Devon, ‡

One Oil Patch Drive, Devon, Alberta T9G 1A8 Alberta Innovates, 10020-101A Ave., Edmonton, Alberta T5J 3G2

ACS Paragon Plus Environment

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GRAPHIC TABLE OF CONTENTS


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ABSTRACT Hybrid bitumen extraction (HBE) at ambient conditions has potential, as an alternative to the currently used modified Clark hot water extraction (CHWE), to reduce thermal energy intensity and greenhouse gas emissions for bitumen extraction from mined ore. Importantly, this extraction method could be retrofitted to the current commercial process. This research focuses on the extent of solvent loss in the sand tailings, which is the most important issue associated with the success and commercialization of HBE. In this work, a series of bench-scale HBE tests were conducted under various conditions and the solvent content in the tailings determined. Results suggest that the amount of solvent in the tailings depends largely on the processability of oil sand ore and the type and dosage of solvent used to soak the ore in the HBE. Only with a good processing ore, for which over 90% bitumen recovery was obtained, solvent losses to tailings were below the regulated volatile organic compound loss limit, without the use of a tailings solvent recovery unit. The correlation between solvent loss to tailings and unrecovered bitumen content is discussed.

Keywords: bitumen extraction, oil sands, solvent, hybrid process, gas chromatography.


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1. INTRODUCTION With over 170 billion barrels of recoverable crude bitumen in place under current technologies,1 Canadian oil sands constitute an important unconventional oil resource and provide a reliable energy supply. Commercially, bitumen is recovered from mined Canadian oil sands using a modified version of the Clark hot water extraction (CHWE) process: mined ore is crushed and conveyed to mix with hot water to form a slurry, which is then transported through pipelines to a primary flotation vessel.2,3 In the primary flotation vessel, liberated bitumen drops engulf air bubbles and then float to the top of vessel, forming bitumen froth containing, on average, 60% bitumen, 30% water, and 10% solids on mass basis.4,5 In order to remove the remaining solids and water, further “froth treatment” is carried out with the help of settlers or centrifugation after the addition of a solvent. Either naphtha (naphthenic froth treatment; NFT) or paraffinic solvents (paraffinic froth treatment; PFT) are used to dilute bitumen froth for froth treatment in oil sand mining operations. The product from NFT at a naphtha-to-bitumen mass ratio of 0.6 to 0.75 usually contains about 2.5 wt% or more contaminants of combined water and solids.6,7 PFT, by adding paraffinic solvent(s) at a solvent-to-bitumen mass ratio of 1.5, produces a fungible bitumen product with less than 0.5% combined solids and water, and the removal of asphaltenes provides a bitumen/solvent mixture with preferential carbon rejection.6,7 In both froth treatment processes, solvent is then subsequently recovered from the diluted bitumen via a solvent recovery unit (SRU), and recycled. Aqueous extraction suffers from several drawbacks and challenges, in particular the intensive consumption of thermal energy and fresh water, emissions of greenhouse gases, managing tailings ponds, and relatively low bitumen recovery for low-grade oil sand ores.


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To address these issues, an alternative extraction method—aqueous/non-aqueous hybrid bitumen extraction (HBE)—was proposed and tested using a bench-scale Denver extraction cell in Dr. Zhenghe Xu’s research group at the University of Alberta.8,9 Details of the experimental protocols and results of laboratory HBE are described by Harjar et al.8 and Lin et al.9 The main findings of their work are as follows: (1) HBE at ambient conditions appears to be feasible and attractive. A small amount of the solvent such as kerosene or toluene, less than 40% of the quantity currently used in naphthenic froth treatment, needs to be distributed up-front as a pretreatment in order to saturate and reduce the viscosity of the mined ore; the current waterbased process is then applied, but at much lower operating temperatures and without caustic addition.8,9 (2) The HBE process is robust, regardless of ore source. Soaking the ore with solvent prior to slurry conditioning is beneficial in significantly enhancing bitumen recoveries at ambient conditions for all grades of ore.8,9 (3) Small additions of polymeric chemical additives during HBE, e.g. ethyl cellulose, which are widely applied in current froth dewatering treatment, further reduce the amounts of solids and water in the bitumen froth without sacrificing bitumen recovery.9 Although the extraction performance of HBE has been promising, there remains a clear necessity to investigate and understand solvent losses to oil sands extraction tailings, which is probably the most important technical obstacle to the success of any solvent-assisted or solventbased process. This paper presents a comprehensive study on the amounts of solvent remaining in the sand during ambient HBE. The concentrations of solvent in these tailings were determined by gas chromatography with flame ionization detection (GC-FID). The amount of unrecovered bitumen was obtained by both Dean-Stark analysis of the collected bitumen froth and o-xylene


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extraction of the extracted tailings. The solvent loss in the tailings was correlated to the unrecovered bitumen content and initial solvent dosage. 2. EXPERIMENTAL 2.1.

Materials. Three oil sand ores from the Athabasca deposit in northern Alberta

were used and marked as OS1, OS2, and OS3. Bitumen, solids, and water contents in these three ores were determined by Dean-Stark extraction and the percentage of fines (solids smaller than 44 µm) in the mineral, expressed as mass fraction in total mineral solids, was determined by wet sieving. Data are given in Table 1. To determine the extractability of the three ores, a batch extraction unit (BEU) was used to conduct bitumen extraction tests in which no solvent was involved. The test procedure is described later. It is clearly shown in Figure 1 that bitumen recoveries for ore OS1 were relatively low at ambient temperature (as expected) and also was low at a warm slurry temperature, using simulated process water (SPW, see below for water chemistry): 10.6% at 20oC and about 43.0% at 50oC. With caustic addition to pH 9.0 at 50oC, bitumen recovery was only 46.9%. For OS2, bitumen recovery was very low at ambient temperature (again, as expected), but increased dramatically to about 97% at 50oC; interestingly (but as often occurs with high-grade ores), recovery decreased slightly to 92.7% when caustic was added. For OS3 ore, bitumen recoveries were relatively high (about 61.1%) at 20oC and continued to improve to 93.0% and 99.3% at 50oC for water pH 8.1 and pH 9.0, respectively. Based on these extractability results, the processabilities of ores OS1, OS2, and OS3 were roughly classified as poor, average, and good, respectively. For aqueous phase in our BEU tests, simulated process water (SPW) was used. This was an electrolyte designated to mimic the chemistry of recycle process water in commercial bitumen extraction operations. SPW was prepared by dissolving 25 mM NaCl, 15 mM NaHCO3, and 2


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mM Na2SO4 and 0.5 mM CaCl2 into deionized water; its pH was determined to be 8.1±0.1, with no further adjustment. All the associated salts purchased from Fisher Scientific were better than 99% in purity. In a few experiments a dilute solution of sodium hydroxide (Fisher Scientific) was added into the SPW to adjust its pH to 9.0, while in others HCl (Fisher Scientific) was used to reduce the pH to 7.5, right prior to its use for BEU extraction. If stored, SPW was confined in a capped pail and could not exchange CO2 with atmosphere. As to very mild alkalinity, no precipitation of calcite was occurred, and the pH value remained unchanged, in SPW during the storage. Organic solvents including n-pentane (C5), n-hexane (C6), n-heptane (C7), and toluene purchased from Fisher Scientific (ACS grade) were used as received.

Table 1. Composition (wt%) and Extractability of Three Oil Sand Ores Ore

Bitumen

Solids

Water

Fines (in solids)

Ore extractability

OS1 OS2 OS3

9.68 11.68 11.35

83.87 84.75 85.60

6.24 3.16 3.02

20.58 24.38 16.31

Poor Average Good

100

Bitumen recovery (%)

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90 80 70

OS1 OS2 OS3

60 50 40 30 20

pH8.1

pH8.1

20

50

pH9.0

10 0

50 o

Temperature ( C)


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Figure 1. Effects of SPW water temperature and pH on bitumen recoveries from the three ores without solvent addition. Bitumen recoveries without caustic addition at 20oC were used as a reference.

2.2.

Preparation of Tailings Samples. A series of bench-scale bitumen extraction

tests were conducted under several experimental conditions to simulate ambient-temperature HBE in order to generate the tailings samples required for analysis. The HBE experiments were performed utilizing a setup and procedure significantly modified compared to previous similar work8,9: (1) Tumbling was used instead of manual mixing to ensure thorough soaking of solvent into the ore. The tumbling procedure can readily be scaled up and applied to pilot- and industrialscale operations; and (2) a batch extraction unit (BEU) was used in this study instead of a Denver extraction cell since the bitumen recoveries and froth qualities obtained by the BEU were shown to surpass those of a Denver cell at the same conditions.10 The BEU apparatus in this study, which was similar to those used by Syncrude Research for several decades, consisted of 1.2-L extraction pot, water jacket and circulating bath, impeller and driveshaft, air flow system and measure meter, motor and tachometer, and the stand. BEU was first designed by Sanford and Seyer,11 where details of the BEU itself were given. Consistent with those used by Harjar et al.8 and Lin et al.9, the current HBE protocol is presented schematically in Figure 2. In the first step, a desired amount of a solvent is mixed uniformly into the oil sand ore by the tumbling action of a roller (US Stoneware, Serial No. CZ-07072) at 60 rpm, and the energy input for this mixing is estimated at about 100 kJ. The tests confirming that tumbling is a sufficient method of uniform mixing will be illustrated later. Immediately following 30 min of tumbling, the soaked oil sand ore (approximately 500 g) was quickly transferred to the BEU unit where 200 g of SPW was added to make a slurry at the desired temperature. A temperature of 20oC was maintained using a


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water jacket and a temperature-controlled circulating bath connected to the BEU unit. After the slurry had been conditioned for 20 min, 850 g of SPW was added in the BEU, immediately followed by air introduced at a rate of 3.9 mL/s. The froth was collected after 15 min of flotation and then analyzed for bitumen, solids, water by Dean-Stark extraction. Bitumen recovery is expressed as the ratio of the mass of bitumen recovered in froth to the total bitumen mass in the oil sand ore. After froth collection, the remaining suspension, which included most of the solids and water and trace amounts of bitumen and solvent, was ejected from the bottom of BEU as the extracted oil sand tailings. Samples were taken to be analyzed for solvent content as well as bitumen content in the tailings. A custom-built cover for the BEU that held ice was used in order to minimise solvent loss to the surroundings during extraction tests. The focus in this study was on the paraffinic solvents n-hexane (C6), n-pentane (C5), and n-heptane (C7). Toluene was used as a reference example of a good solvent for solubilizing bitumen.9 Depending on the grade of ore, the quantity of solvent added was 0.55 wt% to 3 wt% of the mass of ore sample, corresponding to about 5 wt% to 30 wt% scaled by the mass of bitumen in the ore.

Solvent

2nd Water

Oil Sands Tumbling

(30 min)

Conditioning (20 min)

1st Water

Bitumen Flotation Froth

(15 min)

Tailings Analysis of solvent loss


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Figure 2. Schematic protocol of tailings production from a hybrid bitumen extraction process: the solvent was distributed evenly in the ore by mixing the solvent and ore in a tumbler prior to slurry conditioning and flotation; tailings samples were taken for analysis of solvent content. Tests were conducted to confirm whether tumbling was sufficient to ensure uniform distributions of small amounts of solvent (hexane or toluene) into the oil sand ore matrix. A weighed oil sand sample was loaded in a 1-L cylindrical jar and the desired amount of solvent was added on top. The jar was capped, then placed horizontally and rolled (i.e. tumbled) between two rows of rollers for a defined time. There was no loss of volatiles including n-pentene during the tumbling as there was no change in the total weight after tumbling. In order to minimize potential evaporation losses of a volatile solvent from the soaked ore during sample transfer, the jar containing the sample of ore and solvent mixture, after being tumbled, was kept at a maximum of 4oC for at least 4 h. Portions (typically 20 to 30 g) of soaked ore taken from different locations in the jar were then quickly transferred to chilled containers for solvent content measurements. The solvent in the soaked samples was quantified by o-xylene extraction12 followed by centrifugation and GC-FID analysis as described in section 2.3 (see Figure 3). The hexane or toluene solvent contents of samples taken from different locations in the jar after 0.5 or 2 h tumbling were measured. It was evident that solvent contents at different locations in the soaked ore were all within 10% of the fixed initial dosage of solvent, and that 30 min of tumbling was sufficient to uniformly distribute the added solvent into the bitumen. No significant difference in standard deviation from the average solvent content in the soaked ore was noticed for samples tumbled with solvent for 30 min as compared to those soaked for 2 h. In addition, the results of bitumen recoveries for BEU tests, shown in section 3, also demonstrate that rotary tumbling is an efficient mixing method and that 30 min of tumbling is sufficient at a lab scale.


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2.3.

Quantification of Solvent in Tailings. As illustrated in Figure 3, solvent and

bitumen were extracted from mineral solids and water in the tailings sample using o-xylene extraction followed by centrifugation12 at about 1500 g-force for 30 min. Bitumen content was determined gravimetrically by drying filter paper to which had been added 5 mL aliquot of the centrifuged o-xylene extract, and drying was done at room temperature in a fume hood for 2 hours. Solvent content in the centrifuged extracts was directly quantified using an Agilent Technologies 7890 gas chromatograph equipped with a flame ionization detector (GC-FID).

Figure 3. Process flow diagram illustrating the o-xylene extraction and centrifugation procedure for extracting residual solvent and bitumen from solids and water in the tailings sample. In

the

GC-FID

analysis,

an

HP-1

(stationary

phase

100%

cross-linked

dimethylpolysiloxane) capillary column 25 m in length, 0.32 mm in internal diameter, with 0.17 µm film thickness was used. The carrier gas was helium and the column gas flow rate was 1.4


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mL/min, with head pressure 0.5 psi. The injection temperature and the FID temperature was 250oC. The column oven was held at 30oC for 1 min, and then linearly increased to 50oC at a rate of 3oC/min. The column was then heated to, and held at 200oC for 10 min to clear all the amount of o-xylene, from the column. Bitumen (asphaltenes) residues that could not be expelled in the post run were detained by glass wool in the bottom of inlet liner connected to GC column, and timely replacement of inlet liner with glass wool was performed. An example of a chromatogram with temperature profile is illustrated in Figure 4. As can be seen, each solvent in the mixture has its own unique retention time and peak.12,13 The area under each peak is compared with a known amount of an internal standard (n-octane in this case) to determine the solvent content.14 As o-xylene was expelled in post run, there was no peak of o-xylene in the GC spectra shown in Figure 4. It is important to note that bitumen is an ultra-viscous oil, with negligible amount of compounds with boiling point below 200oC.15-18 Our baseline GC-FID analysis with bitumen-in-xylene solution revealed that there was no peak during the first 7.667 min of retention time, suggesting bitumen did not contain detectable amount of hydrocarbons lighter than boiling 140oC.


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Column: HP-1, 25 m x 0.32 mm ID, 0.17 µm thickness Carrier: Helium, 1.4 mL/min constant flow Detector: FID 250oC 200oC

post run: 10 min

5

50oC

30oC 1min 1. 2. 3. 4. 5.

0

n-pentane n-hexane n-heptane toluene n-octane

2

3 4

1

2

4 6 Retention Time (min)

8

Figure 4. Illustration of chromatographic spectra of volatile hydrocarbons in the mixture of xylene-diluted bitumen solution and the respective temperature profile of the column oven as a function of retention time using GC-FID.

3. RESULTS AND DISSCUSSION 3.1.

Effect of Solvent Dosage. Figure 5 shows the amount of residual solvent content

in the extraction tailings for three ores at various dosages of n-hexane used to pretreat the ore in the ambient-temperature HBE. The y-axis represents the dimensionless volume loss of solvent to the extracted tailings, relative to 1000 volumes bitumen produced, denoted as . is a parameter that government regulators and industry operators use to measure the amount of solvent lost, and must be held to a minimum value. 4 barrels (bbl) lost per 1000 bbl bitumen produced is a threshold value set by the Alberta Energy Regulator (AER) for the collective solvent loss. Note that the amount of solvent remained in the tailings after TSRU from froth


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treatment for commercial aqueous process typically is about 2.5 bbl per 1000 bbl bitumen produced.2,3 As froth treatment operation units are equally applied,8,9 solvent loss to HBE extraction tailings alone should be less than 1.5 volumes per 1000 volumes bitumen produced (i.e. < 1.5). A value of = 1.5 corresponds to approximately 100 ppm n-hexane per mass of water-dry tailings, if 90% bitumen recovery is achieved for ore containing 11% bitumen. was calculated using the following equation:

=

×

× 10

(1)

where and are the densities of raw bitumen and solvent, respectively. M is the total mass of bitumen extracted and collected in the bitumen froth, which was obtained directly by Dean-Stark analysis of the froth, or indirectly by the analyzing bitumen content in the tailings.

M is the total mass of solvent lost to the whole tailings and is obtained as follows:

M = M where M

'

×

! "# !$

= M

×

! "%& !$

×

! "# ! "%&

(2-i)

is the total mass of the whole tailings produced by the HBE process. '()* and

are the masses of o-xylene and tailings sample, respectively, used in the o-xylene

extraction of tailings. '(, is the mass of solvent in the whole supernatant after the o-xylene extraction of tailings. Since the solvent, xylene and bitumen are miscible with each other, and the extract (i.e. sub-sample) used for GC-FID analysis was taken from the supernatant and then added in internal standard, it is reasonable to assume the equality of the following ratios: ! "# ! "%&

=

! ! "%&"

(2-ii)

Here, ' and '()*( are the masses of solvent content and o-xylene in the extract, respectively, used for GC-FID analysis. Note that the quantities of '(, and ' are not


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equal; nor are equal between '()* and '()*( . When the mass of the extract for GC analysis is denoted as '(-. , we would have: ! ! "%&"

=

! !"/0

/

! "%&"

(2-iii)

!"/0

The extract for GC analysis is consisted of the solvent, xylene, bitumen and internal standard, it is obvious to have: ! "%&" !"/0

=1−

! !"/0

−

! !"/0

−

!

(2-iv)

!"/0

' and ' are the masses of bitumen content and the added internal standard (n-octane) in the extract, respectively. Combination of the equations (2-i) to (2-iv) would result in:

M = M While M

! "%& , , ! $

×

! "%& !$

and

×

! !"/0

! !"/0

/(1 −

! !"/0

−

! !"/0

were known parameters,

−

! !"/0

! !"/0

and

)

! !"/0

(2) were determined,

respectively, by drying diluted bitumen on filter paper and by comparing the area under the solvent peak ( A ) to the area under the internal standard ( A ) from a GC spectrum as expressed in equation (3), which is simplified from equation (3-i). ! !"/0

=

! !"/0

×

6 6

×7

(3-i)

where 7 is the ratio of the response factor of the solvent to that of the internal standard (i.e. n-C8), or the relative response factor. In GC analysis, the ratio of the mass of a compound to its peak area is defined as the response factor. The 7 -value for each solvent were determined using a series of bitumen-in-xylene solutions containing different known mass ratios of the solvent against the internal standard. As the calibration data showed, the average 7 -values for n-C5, nC6, n-C7, and toluene were 0.98, 1.01, 0.98 and 1.03, respectively, with standard deviations of less than 0.03. Considering the uncertainty and the accuracy of the solution preparation (the


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solvent and n-C8 concentrations on the order of 100-1000 ppm), we suggest that the 7 -value in our study could be considered as unity and no response factor correction was needed. Therefore, when using n-C8 as internal standard to calculate the concentration of n-C5, n-C6, n-C7 or toluene in diluted bitumen solution, equation (3-i) can be simplified to: ! !"/0

=

! !"/0

×

6

(3)

6

As stated previously, the purported advantage of HBE was high bitumen recovery for a variety of ores; however, the amount of solvent needed to achieve reasonably high recovery depends on the extractability and source of the ore.8,9 A relatively high dosage of solvent in the HBE is required for poor-processing ore. As such, in this study, ≤10 wt% hexane, based on the mass of bitumen in the ore, was used in the ore-soaking stage for the good-processing ore OS1, while 30 wt% hexane was required to saturate the poor ore, OS3.

3

3

10

(bbl per 10 bbl bitumen produced)

10

Solvent3 loss in tailings

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OS1 OS2 OS3 2

2

10

10

10

10

1

1 5

7.5

10

15

20

30

Hexane dosage (wt% of bitumen)


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Figure 5. Effect of hexane dosage on residual solvent loss in the respective extracted tailings from bench-scale HBE of oil sand ores OS1, OS2, and OS3 using SPW at 20oC. The residual solvent content is expressed as in units of volume solvent (bbl) per 103 bbl bitumen produced. Results shown in Figure 5 suggest that the amount of solvent (hexane) in the tailings, expressed as , was largely dependent on the dosage of the solvent used to soak the ore in HBE. In particular for OS1 and OS2 ores and the solvent dosage ranges of this study, (as shown on a logarithmic scale in Figure 5) decreased significantly when the hexane solvent dosage was initially increased, and then reversed into an increasing trend when more solvent was added to the ores. for OS2, for example, decreased from 54.6 to 6.5 with increasing hexane dosage from 7.5% to 10% scaled on the mass of bitumen. However, further increasing the hexane dosage from 10 wt% to 15 wt% and then 20 wt% of bitumen leads to increasing amounts of residual hexane in the extraction tailings. Overall, for a good-processing ore, OS3, in which 10 wt% or less (based on bitumen content) hexane achieves high bitumen recovery, solvent losses in the tailings are below the AER limit of 1.5 bbl solvent per 1000 bbl bitumen produced, without the use of a tailings solvent recovery unit (TSRU). For the medium- and poorprocessing ores in which greater amounts of solvent were necessary to enhance bitumen recovery, however, the amounts of residual hexane to the tailings would be well above the AER target without further solvent recovery. Results in Figure 5 also indicate that the amount of solvent lost to the extracted tailings, expressed as , is ore-dependent. At a given dosage of solvent, the overall solvent loss in the extracted tailings decreases sharply in the order of ore OS1 > OS2 > OS3, correlating with increasing extractability of the ores (see Figure 1). It is evident that, given the same 10 wt%


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hexane dosage used to presoak the ore, for example, the solvent loss to the tailings from the poor-processing ore OS1 was about two orders of magnitude greater than those from mediumand good-processing ores OS2 and OS3. It should be noted that it would be desirable to study the effect of the properties of oil sands ore, including fines content and type, and bitumen content, on solvent loss in ambient HBE process. For such investigation at least dozens of oil sands ores are needed to draw a meaningful remark, but limited ores available prevented us to do so. Previous studies showed that the properties of ore are an important factor that affect ore processability (or bitumen recovery) in hot or warm water extraction process.2,3,19,20 With much scatter in the data, there is a trend that good processing ores in aqueous process are associated with low percent fines or high bitumen content.2,19 The effect of fines content on bitumen recovery in aqueous process depends on the type of fines and the water chemistry.20

3.2.

Effect of Solvent Type. It is clearly shown in Figure 6, which compares solvent

loss using pentane (C5) through heptane (C7) and toluene, that using the same dosage for a given ore, the lighter the solvent used in ambient-temperature HBE, the smaller the amount of solvent lost. For the good-processing ore, OS3, with usage of 7.5 wt% solvent per mass bitumen in the ore, for example, the residual solvent content in the tailings from pentane-diluted ore is about 0.57 volumes per 103 volumes bitumen produced, one fifth of that lost to the tailings from the toluene-diluted ore.


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C5 C6 C7 Toluene 10

10

1

1

OS1

OS2

OS3

Figure 6. Effect of solvent type on solvent loss in extracted tailings from bench-scale HBE using SPW at 20oC in units of bbl per 103 bbl bitumen produced for ores OS1 to OS3. Dosages of solvent used for OS1, OS2, and OS3 were 20 wt%, 10 wt%, and 7.5 wt%, respectively, scaled by the bitumen mass in the ore. For the same ore, dosage for different type of solvent was the same per mass bitumen.

3.3.

Effect of Aqueous pH. Results presented in Figure 7 show a significant increase

in the loss of hexane to the OS1 extraction tailings when the pH of simulated process water (SPW) is reduced from 8.1 to 7.5 in ambient-temperature HBE, but the solvent loss levels off when the water pH is increased from 8.1 to 9.0. In these tests, OS1 was extracted with 20 wt% solvent per mass bitumen in the ore.


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Solvent loss in tailings

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0

0 7.5

8.1

9.0

Water pH Figure 7. Effect of process water pH on residual solvent loss in extracted tailings from benchscale HBE at 20oC for OS1 ore, in units of bbl solvent lost per 103 bbl bitumen produced. 20 wt% solvent per mass bitumen in the ore used in extraction.

3.4. Discussion. To understand the fundamentals that underlie the amount of residual solvent in the bench-scale extraction tailings, the respective bitumen recoveries were also quantified by either Dean-Stark analysis of the collected froth or analysis of residual bitumen in the tailings. Results for bitumen recovery from the two methods agreed closely, within reasonable operator error. Figure 8 shows bitumen recovery rates at the above-mentioned extraction conditions.


(a)

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OS1

OS2

OS3

(c)

90

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70 OS1

60 7.5

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Water pH Figure 8. Effect of (a) hexane solvent dosage; (b) solvent type; and (c) water pH on bitumen recovery from bench-scale HBE process for oil sand ores OS1 to OS3 at 20oC.


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Figure 8 indicates that bitumen recovery rates for the three different ores in the HBE process depend largely on solvent dosage used to presoak the ore, but less significantly on solvent type in the extraction stage. When pH of the slurry water (SPW) was increased from 7.5 to 8.1 to 9.0 in the ambient-condition HBE, bitumen recovery for ore OS1 was increased by about 7% in the first step and then levelled off. Note that more than 30 wt% solvent addition is not recommended in the HBE process, as further solvent addition showed diminished gain in bitumen recovery8,9, but could cause the risk of increasing operating cost and solvent loss to tailings. The improvement in bitumen recovery due to presoaking oil sand ore with solvent prior to slurry conditioning in the HBE process is mainly attributed to the reduction of bitumen viscosity; this rationale is supported by several previous studies. For example, Hupka et al.,21-23 Schramm et al.,24 and Zhang25 reported a strong correlation between extraction efficiency and bitumen viscosity, and that bitumen recovery could be optimized by viscosity control using kerosene or naphtha pre-treatment of Utah or Athabasca ores, respectively. In order to achieve satisfactory bitumen recovery, the reduction of bitumen viscosity to less than 1 Pa·s was found to be necessary.21-26 A decrease in bitumen viscosity equivalent to that achieved by increasing operating temperature can be also achieved through solvent addition; increasing solvent dosage by even a few percent can reduce bitumen viscosity exponentially.27-30 For a given water chemistry, reducing bitumen viscosity to an optimal value makes the bitumen layer more fluidlike thus facilitating bitumen liberation from sand grains,31-33 bitumen droplet coalescence,34,35 and bitumen-air attachment36-38— the three fundamental steps of bitumen flotation. There is evidence that the viscosity of original bitumen may vary considerably, depending on the source of ore and the asphaltene content.9,27,30,32 It is obvious that to achieve a desired viscosity


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Energy & Fuels

threshold value, the amount of solvent addition would depend on the original bitumen viscosity and oil sand grade.9,32 This is a contributing factor in explaining the above-motioned point that a much higher dosage of solvent is required to increase bitumen recovery of the poor-processing ore OS1 to a reasonable level. It is noted that the relatively high bitumen unrecovered for ore OS1 was mainly attributed to high unliberated bitumen from ore. Previous studies

9,32

also

suggested that at the same dosage of a solvent, a poor-processing ore which contained higher viscosity of virgin bitumen, had a slower bitumen liberation dynamics and lower ultimate degree of bitumen liberation than relatively higher processing ore, resulting in lower bitumen recovery in the HBE process. In addition, light paraffinic solvents such pentane, hexane, and heptane, at equivalent concentrations, are as effective as a light aromatic solvent (toluene in this case) of similar molecular weight in reducing bitumen viscosity,27,29,32 leading to similar bitumen recoveries as shown in Figure 8b by different solvent types for the same amount of solvent addition in the HBE process. It is worthwhile mentioning that for the solvent dosage range of our study in which solvent-to-bitumen ratios (S/B) were no more than 0.3, and so well below the onset concentration for triggering asphaltene precipitation, the paraffinic solvents did not cause deasphalting in the HBE process. As mentioned earlier, it is very challenging to study the impact of individual clays and their surface properties on HBE bitumen recovery and the associated solvent loss when testing the whole ore sample, because of the very complexity and heterogeneity of Canadian oil sands as well as the limited ores available. However, it could be helpful to overview the previous studies regarding the capabilities of model clay particles in retaining organic materials or liquids.39-46 For example, Pourmohammadbagher and Shaw applied solution calorimetry to probe organic liquid transport to and from clay surfaces and provided a theoretical interpretation.39 The results


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showed that trace of soluble toluene or heptane in water could displace sorbed water from kaolinite or illite clay surface.39 Using the same technique, the authors stated that kaolinite and illite clays with coated asphaltenes were less hygroscopic, with the similar or increased capacity of sorb organic liquids.40 Osacky et al. reported that specific surface area of clay particles mainly controlled the amount of organic materials retained on the non-swelling model clays after nonaqueous extraction and solvent removal, with cation exchange capacity and layer charge density as secondary contributing factors.42 The results suggested the increased solvent retention ability of model clay particles when adsorbed by bitumen components and the correlations of clay surface characteristics with the retained organic amount.42


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Energy & Fuels

Figure 9. Correlation between solvent losses to bench-scale extraction tailings and percentage of unrecovered bitumen. Solvent losses are expressed in units of bbl per 103 bbl bitumen produced. Percentage of bitumen uncovered ( = 100 − bitumen recovery ) is defined as the mass percentage of bitumen ending up in tailings to the total bitumen mass in the oil sand ore. The pattern-lined area represents the estimated maximum bitumen unrecovered in the HBE process, in order to meet the AER regulated target for solvent losses. For the solvent loadings used to presoak the ore in all the conditions, solvent-to-bitumen mass ratios were no more than 0.3, and well below the onset concentration for inducing asphaltene precipitation. To appreciate the role of bitumen recovery in controlling solvent distribution, the amount of solvent loss in the extraction tailings is plotted in Figure 9, as a function of unrecovered bitumen percentage for all HBE extraction conditions tested. It appears that, regardless of ore type and solvent, there exists a strong correlation between the solvent loss to tailings (in units of volume per 1000 volumes bitumen produced) and the percentage of unrecovered bitumen: the smaller the bitumen loss to tailings (i.e. higher bitumen recovery), the less residual solvent is entrained in the bench-scale extraction tailings. This correlation between residual solvent and residual bitumen amounts is mainly due to strong solvent partitioning into the organic component (bitumen residue in this case) of the tailings, as expected from the principle of “like dissolves like”. A similar conclusion was drawn by previous researchers on the key parameters that affect solvent losses to the extraction waste in the non-aqueous extraction (NAE) processes.46-49 For example, Nikakhtari et al. reported that higher residual bitumen content in the tailings reduced the cyclohexane solvent drying rate after a non-aqueous extraction process.47 Tan et al. also demonstrated a more dramatic solvent sorption capacity and slower desorption rate on bitumen-coated fine solids than on the bare fines.46 The data in Figure 9 suggest that, to minimize solvent losses to the tailings from an aqueous/non-aqueous hybrid bitumen extraction (HBE) process, sufficiently high (more than 90%) bitumen recovery is required.


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 10. Relation between the ratio of solvent loss and bitumen loss (i.e. unrecovered bitumen percentage) to bench-scale extraction tailings.

Here, solvent loss ratio is defined as the

normalized mass ratio of solvent loss in the tailings over the initial solvent addition used in extraction process. Symbols represent the experimental data points obtained under the various extraction conditions. Lines are a linear regression modeling with no intercept term (y = k • x) between solvent loss ratio (y) and bitumen loss ratio (x) for each solvent. k is the slope of the line and R2 is the coefficient of determination indicating the fit of the regression line to the experimental data. Besides the impact of unrecovered bitumen content, it is interesting to note the effect of solvent-bitumen interaction on solvent loss to the tailings in the HBE process. Figure 10


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Energy & Fuels

summarizes the effect of solvent type on the relation between the ratio of solvent loss and unrecovered bitumen ratio for all the HBE conditions of our study. Here the solvent loss ratio is defined as the mass ratio of solvent loss in the tailings over the initial amount of solvent used to presoak the ore in HBE. Linear relationships between solvent loss to bitumen loss ratios for light alkanes of pentane to heptane with slopes less than one, as shown in Figure 10, indicate that these paraffinic solvents are more prone to partition into the bitumen in the froth than the bitumen in the tailings. However, for toluene, the slope of the two loss ratios is about 1.0, suggesting that toluene is partitioned approximately equally between the froth bitumen and tailings bitumen. This may be attributable to the non-homogenous distribution of saturates, aromatics, resins and asphaltenes (SARA) factions in the bituminous layer of Athabasca oil sands. Previous studies suggested that light and nonpolar fractions, such as saturates, tended to predominate in the outer bituminous layer, while higher-polarity fractions such as asphaltenes, having stronger adhesion to sand grains, were distributed at the inner layer.50-54 To this end, we compared the asphaltene contents of bitumen in the froth extracted from the HBE process using n-pentane or toluene as an extraction solvent against those in the ore. Bitumen was separated from water and solids in the ore or in the froth using a Dean-Stark method. The bitumen-intoluene solution after Dean Stark was vacuum distillated to evaporate toluene and obtain the bitumen. Asphaltenes were precipitated from the bitumen by using the standard ASTM D2007 method.55,56 Results are shown in Figure 11. It is evident that, for the same ore, the asphaltene content of bitumen in the ore was comparable to that in the froth extracted from the HBE process in which toluene was used to presoak the ore. However, bitumen in the froth extracted from the HBE with pentane soaking contained significantly lower asphaltene percentage than bitumen in the given ore. Such observed difference could also be a possible indicator of a complex,


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

inhomogeneous distribution of SARA fractions recognized in previous studies.50-54 Light linear paraffinic solvent would possibly be more capable of extracting the outer bituminous layer with less asphaltene content, than bitumen layer immediately on the surface of sand grains where asphaltenes predominately located. However, the underling mechanism behind the discrepancy in “solvent partitioning” by different solvents remains to be further explored. Figure 10 also clearly shows that, regardless the source of ore, the weaker the solventbitumen interaction and the lighter the paraffinic solvent used to pre-soak the ore in the extraction process, the smaller the slope between solvent loss and bitumen loss ratios. In other words, at an identical unrecovered bitumen content, the lightest paraffinic solvent n-pentane produces the lowest solvent loss ratio, followed by hexane and heptane, and then the aromatic solvent, toluene. This suggests that lighter paraffinic solvent, with a weaker solvent-bitumen interaction, had a smaller solvent loss ratio. Similarly, Wu and Dabros showed that solvent with a lower boiling point (higher volatility) had less residual solvent in the tailings from a nonaqueous extraction process, after drying.14 Nikakhtari et al. also observed that solvent loss to the tailings from a non-aqueous extraction process after drying was reduced linearly as the boiling temperature of the solvent decreased.57 However, it is apparent that the use of very volatile solvents such as pentane would pose significant challenges in controlling solvent losses during the solvent and ore blending stage in a commercial-scale extraction process. Engineering design for use of a suitable solvent in a larger HBE extraction process should carefully consider the delicate balance between the amount of solvent left in the tailings and solvent volatility during extraction, bearing in mind the imperative of ensuring sufficiently high bitumen recovery.


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Asphaltene mass fraction (%)

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30 28 26 24 22 20 18 16 14 12 10 8

ore bitumen froth bitumen by HBE with Toluene soaking froth bitumen by HBE with C5 soaking

OS1

OS2

30 28 26 24 22 20 18 16 14 12 10 8

OS3

Figure 11. Asphaltene mass fractions (wt%) of bitumen in the froth extracted from the hybrid bitumen extraction (HBE) process at which n-pentane (C5) or toluene was used as an extraction solvent to presoak the oil sands ore, for ores OS1 to OS3. Here, asphaltene content of bitumen in the original ore was used as a reference.

4. CONCLUSIONS In this study, the concentrations of solvent in the tailings generated from bench-scale hybrid bitumen extraction (HBE) were determined as a function of extraction conditions using gas chromatograph equipped with flame ionization detection. Results suggest that solvent losses to the extraction tailings in the ambient HBE process are controlled by several factors including ore extractability, solvent type, and solvent dosage. Most importantly, solvent losses to the HBE


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tailings are well correlated with the unrecovered bitumen content. For a good processing ore from which more than 90% bitumen recoveries were achieved using 10 wt% (based on bitumen content) or less initial solvent addition to presoak the ore, the amount of solvent loss to tailings was able to comply with the regulated target, without the use of a tailings solvent recovery unit. Remediation strategies for reducing bitumen and solvent losses for average- and poorprocessing ores to an acceptable level, are the subjects of ongoing research interest, as lowtemperature HBE advances into larger-scale testing and further evaluations as an alternative technology to current commercial hot-water-based extraction.

■ AUTHOR INFORMATION Corresponding Author

* Email: [email protected]; Tel.: +1-780-987-8672. Notes The authors declare no competing financial interest. © Her Majesty the Queen in Right of Canada, as represented by the Minister of Natural Resources, 2018.

■ ACKNOWLEDGEMENTS Financial support from Government of Canada’s interdepartmental Program of Energy Research and Development, PERD, and Alberta Innovates is greatly appreciated.

■ REFERENCES (1)

Radler, M. Oil Gas J. 2002, 100, 113-145.


Page 30 of 34

Page 31 of 34 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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(2)

Masliyah, J. H.; Czarnecki, J. A.; Xu, Z. Handbook on Theory and Practice of Bitumen

Recovery from Athabasca Oil Sands ─ Vol. 1: Theoretical Basis; Kingsley Publishing Services: Kingsley, Calgary, Alberta, Canada, 2011. (3)

Czarnecki, J., Masliyah, J., Xu, Z., Dabros, M. Handbook on Theory and Practice of

Bitumen Recovery from Athabasca Oil Sands ─ Vol. 2: Industrial Practice; Kingsley Knowledge Publishing: Cochrane, Alberta, Canada, 2013. (4)

Xu, Y.; Dabros, T.; Hamza, H. J. Disper. Sci. Tech. 2007, 28, 413-418.

(5)

Long, Y.; Dabros, T.; Hamza, H. Fuel 2002, 81, 1945−1952.

(6)

Long, Y.; Dabros, T.; Hamza. H. Selective Solvent Deasphalting for Heavy Oil Emulsion

Treatment in Asphaltenes, Heavy Oils, Petroleomics (Edited by Mullins, O. C.; Sheu, E. Y.; Hammami, A.; Marshall, A. G.); Springer: New York, USA, 2007. (7)

Rao, F.; Liu, Q. Energy Fuels 2013, 27, 7199-7207.

(8)

Harjai, S. K.; Flury, C.; Masliyah, J.; Drelich, J.; Xu, Z. Energy Fuels 2012, 26, 2920-2927.

(9)

Lin, F.; He, L.; Hou, J.; Masliyah, J.; Xu, Z. Energy Fuels 2016, 30, 121-129.

(10) Curran, M.; Tamiz, M. B.; Chen, T; Zhu, J.; Xu, Z. A Review of Laboratory Based

Extraction Methods for Bitumen Recoveries: The Role of Caustic; NSERC IRC Oil Sands Engineering Meeting, Syncrude Canada Limited: Edmonton, Alberta, Canada, 2013. (11) Sanford, E. C.; Seyer, F. A. CIM Bulletin 1979, 72, 164-169. (12) Reference Method for the Canada Wide Standard for Petroleum Hydrocarbons in Soil –

Tier 1 Method; Canadian Council of Ministers of the Environment: Winnipeg, Manitoba, Canada, 2001. (13) Skoog, D. A.; Leary, J. J. Principles of Instrumental Analysis, 4th Ed.; Saunders College Pub.: Philadelphia, Pennsylvania, USA, 1992.


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

(14) Wu, J.; Dabros, T. Energy Fuels 2012, 26, 1002-1008. (15) Subramanian, M.; Deo, M. D.; Hanson, F. V. J. Chromatographic Sci. 1996, 34, 20-26. (16) Strausz, O. P.; Morales-Izquierdo, A.; Kazmi, N.; Montgomery, D. S.; Payzant, J. D.; Safarik, I.; Murgich, J. Energy Fuels 2010, 24, 5053-5072. (17) Strausz, O. P.; Lown, E. M.; Morales-Izquierdo, A.; Kazmi, N.; Montgomery, D. S.; Payzant, J. D.; Safarik, I.; Murgich, J. Energy Fuels 2011, 25, 4552-4579. (18) Selucky, M. L.; Chu, Y.; Ruo, T.; Strausz, O. P. Fuel 1977, 56, 369-381. (19) Cameron Engineers, Oil Sands in Synthetic Fuels Data Handbooks: U.S. Oil Shale, US

Coal, Oil Sands ed. G. L. Baughman. Denver, Colorado, USA, 1978. (20) Wallace, D.; Tipman, R.; Komishke, B.; Wallwork, V.; Perkins, E. Can. J. Chem. Eng. 2004, 82, 667-677. (21) Hupka, J.; Miller, J. D.; Cortez, A. Miner. Eng. 1983, 35, 1635-1641. (22) Hupka, J.; Miller, J. D. Miner. Metall. Process. 1993, 139-144. (23) Hupka, J.; Miller, J. D.; Drelich, J. Can. J. Chem. Eng. 2004, 82, 978-985. (24) Schramm, L. L.; Stasiuk, E. N.; Yarranton, H.; Maini, B. B.; Shelfantook, B. J. Can. Pet.

Technol. 2003, 42, 55-61. (25) Zhang, M. Role of Bitumen Viscosity in Bitumen Recovery from Athabasca Oil Sands. M.Sc. Thesis, University of Alberta, Edmonton, Alberta, Canada, 2012. (26) Long, J.; Drelich, J.; Xu, Z.; Masliyah, J. H. Can. J. Chem. Eng. 2007, 85, 726-738. (27) Seyer, F. A.; Gyte, C. W. AOSTRA Technical Handbook on Oilsands, Bitumens and Heavy

Oils 1989, 6, 153-184. (28) Masliyah, J. H.; Gray, M. R. Extraction and Upgrading of Oil Sands Bitumen-Intensive

Short Course, University of Alberta, Edmonton, Alberta, Canada, 2011.


Page 32 of 34

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Energy & Fuels

(29) He, L.; Lin, F.; Xu, Z.; Li, X.; Sui, H. Chem. Soc. Rev. 2015, 44, 5446-5494. (30) Lin, F.; He, L.; Primkulov, B.; Xu, Z. J. Phys. Chem. C 2014, 118, 13552-13562. (31) Srinivasa, S.; Flury, C.; Afacan, A.; Masliyah, J.; Xu, Z. Energy Fuels 2012, 26, 2883-2890. (32) He, L.; Lin, F.; Li, X.; Xu, Z.; Sui, H. Energy Fuels 2014, 28, 7403-7410. (33) Primkulov, B.; Lin, F.; Xu, Z. Colloids Surf. A: Physicochem. Eng. Aspects 2016, 497, 336343. (34) Esmaeili, P.; Lin, F.; Yeung, A. Langmuir 2012, 28, 4948-4954. (35) Moran, K. Langmuir 2007, 23, 4167-4177. (36) Gu, G.; Xu, Z.; Nandakumar, K.; Masliyah, J. Int. J. Miner. Process. 2003, 69, 235-250. (37) He, L.; Lin, F.; Li, X.; Xu, Z.; Sui, H. Chem. Eng. Sci. 2015, 137, 31-39. (38) Lelinski, D.; Drelich, J.; Miller, J. D.; Hupka, J. Can. J. Chem. Eng. 2004, 82, 794-800. (39) Pourmohammadbagher, A.; Shaw, J. M. Environ. Sci. Technol. 2015, 49, 10841-10849. (40) Pourmohammadbagher, A.; Shaw, J. M. Energy Fuels 2016, 30, 6561-6569. (41) Pourmohammadbagher, A.; Shaw, J. M. Energy Fuels 2016, 30, 5964-5969. (42) Osacky, M.; Geramian, M.; Ivey, D. G.; Liu, Q.; Etsell, T. H. Energy Fuels 2015, 29, 41504159. (43) Lebedeva, E. V.; Fogden, A. Colloids Surf. A 2011, 377, 115-122. (44) Goss, K. Environ. Sci. Technol. 1992, 26, 2287-2294. (45) Goss, K. Environ. Sci. Technol. 1993, 27, 2127-2132. (46) Tan, X.; Vagi, L.; Liu, Q.; Choi, P.; Gray, M. R. Can. J. Chem. Eng. 2016, 94, 220-230. (47) Nikakhtari, H.; Pal, K.; Wolf, S.; Choi, P.; Liu, Q; Gray, M. R. Can. J. Chem. Eng. 2016,

94, 408-414. (48) Noorjahan, A.; Tan, X.; Liu, Q.; Gray, M. R.; Choi, P. Energy Fuels 2014, 28, 1004-1011.


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

(49) Lin, F.; Stoyanov, S. R.; Xu, Y. Org. Process Res. Dev. 2017, 21, 492-510. (50) He, L.; Li, X.; Wu, G.; Lin, F.; Sui, H. Energy Fuels 2013, 27, 4677-4683. (51) Fritschy, G.; Papirer, E. Fuel 1978, 57, 701-704. (52) Abraham, T.; Christendat, D.; Karan, K.; Xu, Z.; Masliyah, J. Ind. Eng. Chem. Res. 2002,

41, 2170-2177. (53) Liu, J. J.; Xu, Z.; Masliyah, J. Langmuir 2003, 19, 3911-3920. (54) Wu, G.; He, L.; Chen, D. Chemosphere 2013, 92, 1465-1471. (55) Luo, P.; Gu, Y. Fuel 2007, 86, 1069-1078. (56) Ghanavati, M.; Shojaei, M. J.; Abadi, A. R. S. Energy Fuels 2013, 27, 7217-7232. (57) Nikakhtari, H.; Vagi, L.; Choi, P.; Liu, Q.; Gray, M. R. Can. J. Chem. Eng. 2013, 91, 11531160.


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Determination and Understanding of Solvent Losses to Tailings from a

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