Catalytic Pyrolysis of Used Engine Oil over Coal Ash into Fuel-like

Article pubs.acs.org/EF

Catalytic Pyrolysis of Used Engine Oil over Coal Ash into Fuel-like Products Imtiaz Ahmad,*,† Razia Khan,† Mohammad Ishaq,† Hizbullah Khan,‡ M. Ismail,† Kashif Gul,† and Waqas Ahmad† Institute of Chemical Sciences and ‡Department of Environmental Sciences, University of Peshawar, 25120 Peshawar, Khyber Pakhtunkhwa, Pakistan

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ABSTRACT: The present paper reports on the conversion of spent lubricating oil (SLO) into useful fuel-like products through two-stage pyrolysis. Liquid pyrolysates (LPs) from the first stage were obtained using prebaked clay (PBC) as adsorbent and subjected to second stage pyrolysis over coal ash (CA) as catalyst. The PBC and CA were characterized by using morphological, elemental, surface, and crystallographic properties. The influence of CA concentration on the yield of LPs and their compositions in terms of hydrocarbon range and hydrocarbon group type’s distributions were studied. Fuel properties such as density, specific gravity, API gravity, ash content, kinematic viscosity, pour point, aniline point, diesel index, cetane number, and calorific value of the thermally derived pyrolysate (TDLP) as well the catalytically derived liquid pyrolysate (CDLP) in comparison with the ASTM standard values were also studied. The results indicate that the CA when used in low concentration exhibited good activity and selectivity toward formation of the LPs having fuel value comparable with diesel fuel.

1. INTRODUCTION Lubricating oil after use ends its life as a waste. Due to the tremendous increase in the number of vehicles and other means of transportation, hundreds of tons of spent oil is produced daily,1 and only in Pakistan, a substantial quantity of used engine oils from different sources is disposed off as a harmful waste into the environment.2 This careless disposal is a serious issue with respect to wastage of a valuable resource and consequent environmental problems. Spent oil is disposed of by several methods, including incineration and indiscriminate land filling.3−5 The presence of toxic impurities in these waste streams in the form of air borne dust, wear metals, sulfur, polyaromatic hydrocarbons (PAH), soot, oxidation products, depleted additive remnants, etc. has brought into question the validity of these methods. Hence, it seems feasible and interesting to explore new methods to convert it into environmentally benign useful products instead of throwing it into landfills or subjecting it to incineration, burning, etc. As the lubricating oil is a valuable resource, hence efforts have been made to restore its basic characteristics by reclamation or re-refining.6−10 However, these methods are considered ineffective in dealing with the issue due to strict environmental regulations.11,12 As global reserves of energy resources, particularly fossil fuels, which are depleted at a faster rate due to many-fold expansion in the energy market, are limited, great efforts are being made to preserve these resources by avoiding unnecessary use and by recycling the waste streams from petroleum and automobile industries. It is well understood that the spent lubricating oil contains carbon−hydrogen-based molecules; hence, it can be considered as a source of energy or as a feed stock to get useful chemicals. The recycling of waste lubricant oils into chemical feedstock or fuel oil via pyrolysis may be a suitable option not only to protect the environment from hazardous waste but also to reuse it as a secondary fuel in the automobile industry or © 2015 American Chemical Society

other power generating applications. Catalytic pyrolysis of waste lubricating oil/petroleum residual oil into fuel oil or chemical feedstock has been viewed in the past.13−15 Several heterogeneous catalysts were studied with greater success.16−21 However, there are still shortcomings, including high process and operating costs, competitive poor quality products, catalyst poisoning, and its recovery possibilities or on stream regeneration, etc. Hence, further concerted efforts are needed to overcome these shortcomings. The present work is aimed at two stage recycling of the spent lubricating oil into chemical feedstock or fuel oil. In the first stage pyrolysis, an adsorptive cracking approach with focus on removal of soot and carbonaceous contaminants, additives remnants, and air borne dust was used, employing PBC as adsorbent to recover the clean fraction. In the second stage, the clean fraction from first stage pyrolysis was subjected to cracking over coal ash (CA) as catalyst in order to get volatile/ distillable fractions of fuel value in comparison with the generic diesel fuel.

2. EXPERIMENTAL SECTION 2.1. Chemicals and Reagents. PBC was obtained from a local brick kiln. SLO (PSO DEO 8000 used in a bus for 3000 km mileage) was obtained from a local workshop. The CA was obtained from lignitic-subitumious Pakistani coal (Abbotabad mines) Khyber Pakhtunkhwa through Pakistan Mineral Development Corporation, Islamabad (PMDC). The proximate and ultimate analyses of the raw coal are given in Table 1. 2.2. Preparation of Coal Ash. The as-received coal sample was crushed, ground, sieved through 212 μm, and subjected to ashing using an American Society for Testing and Materials (ASTM) designated Received: October 3, 2015 Revised: December 4, 2015 Published: December 18, 2015 204

DOI: 10.1021/acs.energyfuels.5b02316 Energy Fuels 2016, 30, 204−218

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reminants and wear metals, etc. A number of experiments were carried out under different experimental conditions/with different sets of variables, such as temperature, SLO/PBC ratio, and residence time in order to optimize conditions for obtaining LP in high yield. The temperature was varied from 200 to 400 °C, SLO/PBC ratio from 1 to 5 wt %, and residence time from 15 to 60 min. The optimum temperature, SLO/PBC ratio, and time were decided on the basis of maximum liquid yields. LP was obtained in bulk quantities under the optimized experimental conditions. In second-stage pyrolysis, the LP obtained in first stage pyrolysis was subjected to cracking in the presence of CA as catalyst. The reactions were carried out under previously optimized conditions of temperature and residence time. The catalyst concentration was varied from 1 to 5% for optimization. The total conversion (liquid + gas) and conversion to LP, gas (G), and residue (R) were determined as follows:

Table 1. Proximate Analysis of Raw Coal Sample parameter

value (wt %)

moisture ash volatile matter fixed carbon total sulfur

7 27 11 55 1.42

method [ASTM D3174-12]. The resultant ash was stored in a Petri dish for further characterization and activity tests. 2.3. Pyrolysis. Pyrolysis experiments were performed in a microsteel-made reactor (A). SLO (50 g) was taken into the reactor, which was heated to the desired temperature using a tube furnace (B) in a flow of nitrogen from a cylinder (C). The cracked vapors from the reactor were passed through a water cooled Liebig condenser (D) provided with water circulation though the water inlet (E) and outlet (F). The condensates were collected in a receiving flask (G) as liquid pyrolysate (LP). The noncondensable gases were allowed to flow through a cold trap before being vented from the system and sent to exit through an outlet (H). The residue was carefully collected and weighed. The reactor schematic is provided in Figure 1. The LP

Overall conversion (%) = LP (%) =

WSLO − WR × 100 WSLO

WL × 100 WSLO

G (%) = 100 − [WL + WR] R (%) =

WR × 100 WSLO

(a) (b) (c) (d)

where WSLO, WL, and WR are the weights of spent lubricating oil, LP, and R. 2.4. Analysis and Characterization. 2.4.1. Prebaked Clay and Coal Ash. The morphological, elemental, crystallographic, and surface properties of the PBC and CA were determined. A scanning electron microscope (SEM) equipped with energy dispersive X-ray (EDX) (Model JEOL-Jsm-5910; Japan) was used for morphological and elemental studies. The crystallographic properties were determined by X-ray diffractometer, model JDX-9C, JEOL, Japan, and the surface properties were determined by surface area analyzer (Quantachrome Nova Station A). 2.4.2. Liquid Pyrolysates. 2.4.2.1. Compositional Analysis. A. Fourier Transform Infra Red Analysis. A Fourier Transform Infra Red spectrophotometer (FTIR Prestige-21 Shimadzu, Japan) was used for the purpose. The spectra were obtained within the wavenumber range of 400−4000 cm−1. B. Gas Chromatographic−Mass Spectrometric Analysis. A gas chromatographic−mass spectrometer (GC-MSQP 2010 Shimadzu) was used. The instrument was equipped with an auto injector (ADC201) and a DB-5MS column (25 m × 0.25 mm i.d., 0.25 μm). He was used as carrier gas with flow rate of 1.3 mL/min and split ratio of 50. The injector temperature was kept at 300 °C, and the sample injection volume used was 1 μL. The initial oven temperature was ramped to 100 °C at a rate of 5 °C min−1 and hold time of 5 min, then to 150 °C

Figure 1. Pyrolysis reactor schematic. collected in the reservoir was measured by weight and used for further analysis. The residue was collected as char and weighed. Gas was measured by difference. Pyrolysis was carried out in two stages. The process schematic is provided in Figure 2. First stage pyrolysis was carried out in the presence of PBC as adsorbent in order to remove soot, carbon, catalyst

Figure 2. Process schematic for pyrolysis of spent lubricating oil. 205


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Figure 3. Scanning electron micrographs of adsorbent and catalyst: (a) prebaked clay; (b) coal ash. at a rate of 10 °C min−1 and hold time of 10 min. The temperature was finally raised to 290 °C at a rate of 2.5 °C min−1 with an isothermal hold of 10 min. The peaks in the chromatogram were identified from the data of the National Institute of Standards and Technology-Mass Spectral (NIST-MS) Library. 2.4.2.2. Fuel Properties. The fuel properties of the LPs were determined according to ASTM standard methods in comparison with the generic petroleum distillate fuels. Density (ASTM D-2598), specific gravity (ASTM D-1298), API gravity (ASTM D-1298), ash (ASTM D-482-80), viscosity (ASTM D-445-74), pour point (ASTM D-97), and aniline point (ASTM D-611) were determined. The diesel index (DI) was calculated by using the given formula:

Table 2. Elemental Analysis of Prebaked Clay and Coal Ash weight %

⎛ API gravity (60 oF) × Aniline point (oF) ⎞ DI: = ⎜ ⎟ ⎝ ⎠ 100 Cetane number (CN) was calculated as CN: = 0.72 × diesel index + 10.The calorific value was determined by the bomb combustion method (ASTM D240-14).

elements

PBC

CA

C O Na Mg Al Si K Ca Ti Fe Zn Cu Total

5.13 53.42 0.48 1.57 6.04 19.72 2.39 5.51 0.39 5.35 n.d n.d 100

n.d 53.13 0.21 0.56 12.96 21.45 3.16 0.14 2.18 2.97 1.19 2.05 100

The FT-IR spectrum of the PBC is shown in Figure 6, which features the absorption peaks at 550, 610, and 780 cm−1, which indicate Si−O asymmetric vibrations, and Al−O and Si−O symmetric stretching vibrations. Absorption peaks appearing at 1000, 1420, and 3600 cm−1 correspond to surface Si−O stretching, OH groups of surface water, and OH attached to Si or Al.25 The peak appearing at 2320 cm−1 may be attributed to Si−H configurations.26 The surface properties, such as surface area, pore volume, and pore diameter, were also determined. The results have been compiled in Table 3. It is evident that PBC has the desired properties required for an effective adsorbent.27,28 3.1.2. Coal Ash. The morphology of the CA was studied by SEM. The corresponding micrograph is given in panel b of Figure 3, which evidences a rough surface containing several features, such as plateaus, drills, cleats, caveats, fissures, kernels, etc. The presence of these features indicates a porous texture. The bright reflectance and opaque areas throughout the micrograph indicate the presence of different mineral matter in varying amounts. CA is the residual product obtained from coal by combustion and considered as a rich source of lithophiles, siderophiles and chalcophiles particularly oxides of Al, Si, and Fe with traces of Cu, Ti, Zn, etc. The EDX analysis was performed in order to determine its composition. The results are given in Table 2 and

3. RESULTS AND DISCUSSION 3.1. Characterization of Prebaked Clay and Coal Ash. 3.1.1. Prebaked Clay. The morphology of the PBC was studied by SEM analysis. The micrograph is provided in panel a of Figure 3, which shows its layered morphology with prominent tunnels and large cavities. The surface seems to be nonuniform and mostly comprised of different sized granules. The mineralogical composition of the PBC was studied by EDX analysis (Table. 2 and panel a of Figure 4). It is evident from the results that its major constituents are Si2O3 and Al2O3, which constitute the framework. The other elements present in different concentrations ranging from 0.4 to 5.02% include Na, Mg, K, Ca, Ti, and Fe. The results also indicate the presence of C and O in high concentrations, which may indicate the presence of carbonates. The XRD pattern is shown in Figure 5, which indicates that the clay contains a variety of minerals, with kaolinite and montmorollinite as the major constituents. The characteristic peaks show that some nonclayey materials, such as mica, α-chrystobalite, and quartz, are also present.22−24 The XRD pattern of the PBC closely matches the standard cards of quartz or silicon oxide (SiO), JCPDS no. [01-083-2465], and magnesium iron silicate (Mg1.05Ca0.16Fe0.72Al0.04Ti0.03) (Si1.98Al0.02)O6, JCPDS no. [01-087-0693]. 206


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Figure 4. EDX signatures of adsorbent and catalyst: (a) prebaked clay; (b) coal ash.

Figure 5. XRD pattern of prebaked clay.

The FTIR spectrum of the coal ash (Figure 8) shows major absorption peaks in the range of 580, 610 and 775, 1030, 1420, and 3750 cm−1, which correspond to Si−O asymmetric vibrations, Al−O and Si−O symmetric stretching vibrations, Si−O stretching, OH groups of surface water, and OH attached to Si or Al, respectively.25 The peak appearing at 2320 cm−1 may be attributed to Si−H vibrations. 3.2. Pyrolysis of SLO. The pyrolysis of SLO was carried out in two stages. In the first stage, the SLO was pyrolyzed in the presence of the PBC as adsorbent under different sets of experimental conditions to get clear (without any black ting) LP in a significant amount and to determine the optimum conditions of temperature, time, and SLO/PBC ratio which provide the LP in significant yields.

panel b of Figure 4, which indicate that CA contains oxides of Al and Si as the major constituents. Other mineral constituents determined, including Na, Mg, K, Ca, Ti, Fe, Cu, and Zn, were present in trace quantities. The surface properties, such as BJH surface area, pore diameter, and pore volume, were also determined. The results are given in Table 3. It is evident from the data that the CA possesses a high surface area, pore volume, and pore diameter. The crystallographic properties were determined by XRD. The corresponding profile provided in Figure 7 reveals a mixed phase, i.e. both amorphous and crystalline. The XRD pattern of coal ash closely matches with calcium−aluminum−iron−silicate hydroxylated (Ca 2Al2 )(Al 0.9 Fe 0.1 )(SiO 4 ) 3 (OH) standard JCPDS card number [01-085-1631], and sodium−potassium−aluminum−silicate (Na0.75K0.25)(AlSi3O8) standard JCPDS card number [61-075-1632]. 207


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Further increase in temperature caused the total yield to decrease while the LP yield increased and attained a level of about 94 wt % at 500 °C. The yield pattern at the SLO/PBC ratio of 1:4 was similar to that of 1:3. It can be seen that the pyrolysis begins at 300 °C. The overall yield was achieved in significant quantity with the maximum LP yield of 92%. The results obtained at high temperatures indicate that the yield pattern greatly affected with the increase in temperature. A marked effect of SLO/PBC ratio as well as increase in temperature can be observed from the LP yields pattern. This can be attributed to the fact that, with the increase in temperature, the hydrocarbons present in the SLO undergo cracking to yield low molecular weight products, which then vaporize as volatile products. This conversion from liquid to vapor phase creates an increase of pressure within the reactor that drives the volatiles out of the reactor into the product collection system.29 At temperature 500 °C, which can be attributed to overcracking reactions as a result of degradation of SLO by the free radical mechanism,30 leading to formation of hydrocarbons which are not condensable at room temperature due to faster vapor flow rate as evident from the higher gas yield. It can be inferred from the results that the highest overall and LP yields were obtained using the charge prepared with SLO/PBC ratio of 1:2 when pyrolyzed at 500 °C. This can be attributed to the fact that an increase in adsorbent concentration decreases the formation of volatiles evolved, possibly due to their imbibitions or caging within the clay matrix, where they repolymerized to give char. Further, as the concentration of PBC is increased, the surface with in the reactor is also increased, which causes a decrease in pressure responsible for sweeping of the volatiles into the condenser. Hence, most of the SLO is retained in the reactor and consumed in production of char. 3.2.1.2. Optimization of Residence Time. In the second step, the effect of residence time was investigated on the distribution of the pyrolysis products. The other experimental conditions were kept constant (SLO/PBC ratio of 1:2 and temperature of 500 °C); however, the reaction time was varied. The product yields were studied over 30, 60, 90, and 120 min times. The results are displayed in Table 5, and show that no pyrolysis occurred within 30 min. The time was then extended to 60 min, which gave the overall yield of 93 wt %, whereas the yields of the LP, G, and R were 93.4, 62.3, and 6.6 wt %, respectively. Further increase in time from 60 to 90 min caused the overall yield to increase up to 99.2 wt %, with the LP yield of 95.6 wt %. The G and R yields decreased to 3.6 and 0.8 wt, respectively. Extension in time beyond 90 min caused no significant change in the yield pattern, which remained the same until extension in time up to 180 min. The increase in the yields with extension in time up to 90 min and then the decrease beyond 90 min can be ascribed to the fact that when the residence time decreases, it affects the exposure of the volatiles to secondary reactions which have been reported to be responsible for the formation of gases. Furthermore, residence time has a marked effect on the tertiary cracking reactions/repolymerization, which are reported to be responsible for char formation.31 There is always a competition going on between primary, secondary, and tertiary cracking reactions which depends on several factors, including reaction

Figure 6. FTIR spectrum of prebaked clay.

Table 3. Surface Properties of Prebaked Clay and Coal Ash level property

PBC

CA

BJH surface area (m2 g−1) pore diameter (Å) pore volume (cm3g −1)

300.26 122.78 0.92

70.16 130.53 1.54

In the second stage pyrolysis, the clear LP from the first stage obtained under the optimized experimental conditions was further pyrolyzed in the presence of the CA as catalyst used in different concentrations in order to determine the optimum CA concentration for getting LP in a significant yield. 3.2.1. First Stage Pyrolysis. In the first stage pyrolysis, the SLO mixed with the PBC was pyrolyzed under different experimental conditions. The influence of temperature, SLO/PBC ratio, and residence time was investigated on the overall yield (wt %) and yields of LP, G, and R. 3.2.1.1. Optimization of SLO/PBC Ratio and Temperature. In the first step, pyrolysis of the SLO was carried out using SLO/PBC in different ratios. The temperature was varied from 200 to 700 °C. The yields of pyrolysates as a function of the SLO/PBC ratio are given in Table 4. The data shows a marked effect of SLO/PBC ratio on the overall yield as well on the yields of LP, G, and R. At low temperatures, that is, 200, 300, and 400 °C, using a SLO/PBC ratio of 1:2, no pyrolysates were obtained. However, when the temperature was increased from 400 to 500 °C, the overall yield of 99.2 wt % was achieved. Furthermore, the yield of the LP was also significant (96 wt %) whereas those of G and R were quite insignificant, that is, 3.6 and 8 wt %, respectively. A further increase in temperature from 500 to 600 °C and then from 600 to 700 °C caused the overall yield and yield of LP to decline with the corresponding increase in G and R. At 700 °C, the overall yield decreased to about 87 wt % and the LP yield to 81 wt %, whereas the G and R yields increased up to 5 and 12 wt %, respectively. In order to view the influence of SLO/PBC ratio, the pyrolysis was carried out using charge prepared in 1:3 ratio. The results are given in Table 4. It can be observed that the pyrolysis is started at 300 °C, giving appreciable overall yield of about 98%. However, the yield of the desirable LP was quite low (about 19 wt %) and that of G was very high. 208


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Figure 7. XRD pattern of coal ash.

Table 4. Yields of Different Pyrolysates as a Function of SLO/PBC Ratio and Temperature yield (wt %) SLO/PBC ratio

temp ( oC)

over all

LP

SR

G

1:2

200 300 400 500 600 700 200 300 400 500 600 700 200 300 400 500 600 700

n.d n.d n.d 99.20 97.54 87.26 n.d 98.28 93.95 94.60 93.30 92.35 n.d.a 95.30 89.50 92.76 92.79 93.20

n.d n.d n.d 95.60 92.40 81.94 n.d 19.25 67.60 94.60 92.40 90.40 n.d. 64 86.8 82 80 60.40

n.d n.d n.d 0.80 2.46 12.74 n.d 1.72 6.05 5.40 6.70 7.65 n.d. 4.70 10.48 10.76 12.79 6.80

n.d n.d n.d 3.60 5.14 5.32 n.d 79.03 26.35 n.d 0.90 1.95 n.d. 31.30 2.72 7.24 7.21 32.8

1:3

1:4

Figure 8. FTIR spectrum of coal ash.

time, feed rate, flow rate of the purging gas, etc. At 90 min, the primary cracking reactions might have dominated over the secondary and tertiary reactions. In contrast, upon extension in time beyond 90 min, the yield pattern declined, which may be due to the predominance of the secondary and tertiary reactions. As the significant overall and LP yields were achieved in 90 min, therefore, the same was chosen as the optimum time for further studies. The optimized conditions were then used

a

n.d.: not determined.

and a fair amount of the LP was obtained for use as feed stock in the second stage pyrolysis. 209


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run catalyzed with 1 wt % CA (99.01 wt %) is almost the same as the uncatalyzed thermal run (99.2 wt %). Further increase in concentration from 1 to 5 wt % caused a steady decline in the overall yield from 99.01 to 95 wt %. The influence of CA on the yield pattern of LP was also studied. The results indicate an abnormal trend with the increase in CA concentration. It can be seen that the yield is quite significant in the case of the uncatalyzed thermal run (about 95%) compared with the catalyzed run. In the catalyzed runs, a maximum LP yield of 73% was achieved using 3 wt % CA, which shows a significant decrease. This may be attributed to the fact that catalysts, particularly acidic catalysts, are associated with significant cracking activities, which in turn have a profound effect on the product distribution.30 Owing to the cracking effect of catalyst, the gas yields increased and LP yields decreased. Increase in CA concentration >3 wt % caused the LP yield to decline further. A similar effect can be observed from the results of R. The R yield is quite negligible in the case of the thermal run (0.8%), which increased up to 4.62% in the catalyzed run. In general, the R yields increased from 0.9 to 4.62 wt % with the increase in concentration of CA from 1 to 5 wt %. The gas yields as a function of the catalyst concentration are also given in Table 6 and indicate that the yield is higher in the case of the run catalyzed with 1% CA (44%) compared with the uncatalyzed thermal run (3.6%). Further increase in CA concentration caused a decline in the gas yields. Based on the results, it can be observed that 1 wt % is the optimum concentration of CA for getting maximum overall and significant LP yields. 3.3. Characterization of LP. The TDLP as well as CDLP were characterized by FT-IR and GC-MS analyses in order to study their chemical compositions. Detailed discussion is given as follows: 3.3.1. FT-IR Analysis. FT-IR is a useful tool that provides information about the nature of the hydrocarbons. The FT-IR spectra and the absorption peaks of the two liquid fractions are provided in Figure 9a, b and Table 7. The spectrum of the

Table 5. Yields of Different Pyrolysates as a Function of Residence Timea yield (wt %)

a

residence time (min)

overall

liquid

gas

solid residue

30 60 90 120

n.d 93.40 99.20 99.20

n.d 62.30 95.60 95.60

n.d 31.10 3.60 3.60

n.d 6.60 0.80 0.80

Temperature: 500 °C. Oil/PBC ratio: 1:2.

3.2.2. Second Stage Pyrolysis. In the second stage pyrolysis, the LP obtained in bulk quantity in the first stage pyrolysis was further subjected to cracking in the presence of CA as catalyst. The influence of its concentration on the overall yield and yields of LP, G, and R was also studied. The LP obtained under optimum catalyst to feed ratio was further characterized to investigate its compositional and fuel properties in comparison with the diesel fuel. 3.2.2.1. Influence of CA and Its Concentration on Yields of Pyrolysates. The overall yield and yields of LP, G, and R as a function of catalyst concentration in comparison with the plain run (thermal) are given in Table 6. It is evident from the data that total conversion (overall yield) obtained in the case of the Table 6. Yields of Pyrolysates as a Function of Catalyst Concentration yield (wt %)

run uncatalyzed thermal CA-catalyzed

catalyst conc (wt %)

overall

liquid

gases

solid residue/ coke

00 1 2 3 4 5

99.20 99.01 98.13 97.09 96.15 95.24

95.60 54.12 68.81 73.19 65.22 69.99

3.60 44.89 29.32 23.89 30.93 25.25

0.80 0.99 1.87 2.91 3.84 4.76

Figure 9. FT-IR spectra of liquid pyrolysates obtained from spent lube oil: (a) thermal run; (b) catalyzed run. 210


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compound; besides this, ethylbenzene, 1,8-dimethylnaphthalene, 2,6-dimethylphenanthrene, and naphthalene were also present in high concentrations. Some oxygenated hydrocarbons, mostly alcohols, were also identified, including 3-nonene-1-ol, indene 2,3-dihydro-l,2-dimethyl, and 1-decanol. 2-Hexyloctadecane-1iodo was also present as one of the alkyl halides. The individual hydrocarbons indicate that the samples are enriched in chemical compounds characteristic of hydrocarbons fuels.32−35 3.3.2.2. Hydrocarbon Group Types Distribution. The chemical composition of a typical fuel, whether gasoline, kerosene, or diesel, is directly attributable to both carbon number and compound class, as required by ASTM D396-96 and ASTM D975-96 methods. The GC-MS analyses of the TDLP and CDLP were carried out in order to investigate their chemical compositions. The results (% distribution of different hydrocarbon group types) are depicted in Table 10. It can be seen from the data that the TDLP comprised mostly the paraffinic, olefinic, naphthenic, aromatic, oxygenated, and halogenated hydrocarbons, in the relative proportions 81.30, 10.46, 4.19, 3.06, 0.27, and 0.64%, respectively. In the case of CDLP, the distribution pattern changed as compared to the thermal run. The yield of the paraffins was found to be 72% compared to that of 81.30% for the thermal run. The yield of the olefinic hydrocarbons was relatively higher in CDLP (14%) compared to TDLP (10.46%). The yields of the naphthenes and aromatics were found to be considerably increased in the catalyzed run. The naphthenic content of 7% was obtained in CDLP compared to 4.19% of TDLP. Likewise, the aromatics content increased compared to the thermal run from 3.06 to 5.43%. The relative proportion of oxygenated hydrocarbons was also found to be considerably increased in the case of the catalyzed runs, but still the yield of oxygenated material remained less than 1%. (0.99%) was obtained with the catalyst. Like paraffins, the yield of halogenated hydrocarbons was found to be decreased in CDLP, with the yield of 0.26% for the alkyl halides. The results indicate that the TDLP possesses a high proportion of paraffins, which decreased in the catalyzed run. The proportion of other hydrocarbon groups, that is, the olefinic, naphthenic, and aromatic hydrocarbons, increased in CDLP. The olefins are formed through dehydrogenation reactions catalyzed by the acidic components, such as Al2O3 and SiO2.36 The concentrations of Al2O3 and SiO2 can influence the catalytic activity toward cracking of high molecular weight components.37 As evident from the composition, CA is enriched in Si and Al, which are the acidic components compared to the basic components, such as Na, K, Ca, Mg, Fe, etc. The acidic sites are more dominant compared to the basic sites. It is well established that naphthenic hydrocarbons are formed via dehydrocyclization and aromatics are produced as a result of dehydrogenation reactions. The results of enhanced naphthenic and aromatic contents in CDLP have established the catalytic activity of CA toward these reactions. This can be attributed to the acid and base sites possessed by the CA, which play primary roles in the dehydrocyclization and aromatization.38−40 The catalyst surface properties also play a vital role in this conversion. The paraffins are adsorbed over the catalyst, get dehydrogenate converted to olefins on one catalyst site, then desorb and readsorb on another catalyst active center for cyclization and aromatization.41 The larger extent of cyclization and aromatization reactions that occur within the pores depends on the type of the catalyst.42 As evident from the textural properties of the CA, it has considerable surface properties with

Table 7. Absorptions Peaks in the FT-IR Spectra of the Liquid Fractions Obtained From the Thermal and Catalytic Pyrolysis of the Spent Lube Oil run

position (cm−1)

intensity

assigned configuration

thermal

2953 2922 2852 1680 1640 1540 1463 721 2954 2922 2852 1456 1377 910

medium strong strong strong weak weak strong medium medium strong strong weak strong weak

C−H (CH3) aliphatic C−H (CH3) aliphatic C−H (CH2) aliphatic CC (stretch) olefinic CC (stretch) aromatic CC (stretch) aromatic CH3 (bend) aliphatic CH2(bend) aliphatic C−H (CH3) aliphatic C−H (CH3) aliphatic C−H (CH2) aliphatic CC (stretch) aromatic C−H (bend) aliphatic C−H (bend) aliphatic

catalyzed

TDLP (Figure 9a) shows absorption peaks characteristic of the paraffinic and aromatic hydrocarbons. The spectrum shows a medium peak positioned at 2953 cm−1, which corresponds to C−H (CH3) aliphatic, and strong peaks observed at 2922 and 2852 cm−1, indicating C−H vibrations for (CH3) aliphatic and (CH2) aliphatics. A medium weak absorption peak observed at 1680 cm−1, and consecutive weak peaks at 1640 and 1540 cm−1 show CC stretching vibrations for olefins and aromatics, respectively. A strong absorption peak centered at 1463 cm−1 and a weak peak at 721 show C−H bending vibrations for CH3 and CH2 aliphatic hydrocarbons. The results suggest that the TDLP consists mostly of aliphatic, olefinic, and aromatic hydrocarbons.The FTIR spectrum of the CDLP is given in Figure 9b. The results show absorption peaks for C−H starching of (CH3 and CH2) aliphatics, CC stretching of aromatics and olefins, and C−H bending vibrations of CH3 and CH2 aliphatic hydrocarbons in all profiles. Hence, it can be concluded that the CDLP also consisted of hydrocarbon group types with preponderance of the naphthenic and aromatic hydrocarbons. 3.3.2. GC-MS Analysis. 3.3.2.1. Individual Compounds Identified. The TDLP and CDLP were analyzed by GC-MS in order to identify the individual compounds present as paraffins, olefins, naphthenes, aromatics, and oxygenated hydrocarbons. It can be seen from the data presented in Tables 8 and 9 that both LPs contained similar compounds, but their relative distribution varied. The paraffinic hydrocarbons identified in the LPs were heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, henicosane, docosane, tetracosane, and pentacosane in relatively higher proprtions, usually more than 1%. Alkyl derivatives of these compounds were present in small proportions. Out of the olefinc hydrocarbons, the major olefins were l-heptene, 2,3,4-trimethyl-2-pentene, 2-methyl-1-heptene, l-octene, 1-nonene, and 1-decene. Some higher molecular weight olefins such as 3-hexadecene and their alkyl derivatives were also found but occurred in relatively small concentrations. Among different naphthenic hydrocarbons identified, cyclohexene, cyclobutane, 1-methylcyclohexane, 1-methyl-3propylcyclohexane, l-ethyl-2-heptylcyclopropane, and nonylcyclopropane were the major compounds found in high concentrations. Some higher naphthenes, including cyclotetradecane and cyclotetracosane, were also present in small proportions. The aromatic hydrocarbons included toluene as a major 211


Article

Energy & Fuels Table 8. Individual Compounds Identified in Liquid Pyrolysates from Thermal Run S. No.

name

R. time (min)

area

conc (%)

3.183 4.917 5.186 6.232 8.752 8.833 10.231 10.902 12.561 12.923 13.993 14.750 16.061 16.409 17.277 17.394 19.544 19.741 20.605 20.928 22.255 22.860 23.764 23.905 24.121 24.661 26.116 26.845 28.419 28.493 30.021 32.519 33.224 35.050 37.193 38.285 38.662 40.182 40.470 43.241 44.961 49.328 53.352 55.728 56.047 57.119 59.673 64.195 67.250 70.452

129951 32230 15321 80354 15804 15268 81809 202144 26508 18098 95123 7425 10321 14372 18114 118525 17735 16360 110461 30939 31627 126278 36264 13548 27310 171510 32047 272563 12966 31822 380863 31034 67595 47823 87240 65730 64312 635968 96136 75144 761731 704026 663039 76117 178204 585087 113960 72761 261908 106034 total

1.53 0.38 0.18 0.95 0.19 0.18 0.97 2.39 0.31 0.21 1.12 0.09 0.12 0.17 0.21 1.40 0.21 0.19 1.30 0.37 0.37 1.49 0.43 0.16 0.32 2.02 0.38 3.22 0.15 0.38 4.50 0.37 0.80 0.56 1.03 0.78 0.76 7.51 1.13 0.89 8.99 8.31 7.83 0.90 2.10 6.91 1.34 0.86 3.09 1.25 81.3

2.978 3.032 3.334 3.969 4.646 5.409 5.710 5.902

63183 107074 12288 40997 13474 74245 53896 42980

0.75 1.26 0.15 0.48 0.16 0.88 0.64 0.51

paraffins 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.

heptane octane, 2,5-dimethylheptane, 3-methyloctane octane, 4-methyloctane, 3-ethyl-2,7-dimethylnonane pentane, 3-ethyl-2,4-dimethylnonane, 2-methylnonane, 3-methyldecane octane, 2,3,6-trimethylheptane, 2,5,5-trimethylnonane, 3,7-dimethylnonane, 2-methyl-3-methylene undecane undecane, 5-methylundecane, 3-methyldodecane undecane, 2,6-dimethylundecane, 3,9-dimethyltridecane tridecane, 6-methyltridecane, 4-methyltridecane, 3-methyltetradecane tetradecane, 3-methylpentadecane undecane, 2-cyclohexylpentadecane, 4-methylhexadecane dodecane, 2,6,11-trimethylheptadecane, 2,6,10, 15-tetramethyl heptadecane heptadecane, 8-methylheptadecane, 2-methylheptadecane, 3-methyloctadecane tritetracontane tetratriacontane nonadecane eicosane henicosane hentriacontane pentatriacontane docosane oetacosane tetracosane pentacosane hexacosane

1. 2. 3. 4. 5. 6. 7. 8.

1-hexene, 2-methyll-heptene 2-heptene, (e) l-hexene, 2,3-dimethyl1-octene, 3,7-dimethyl2-pentene, 2,3,4-trimethyll-heptene, 2-methyl 1-octene

olefins

212


Article

Energy & Fuels Table 8. continued S. No.

name

R. time (min)

area

conc (%)

6.500 6.788 7.823 8.204 9.901 10.462 10.578 13.460 13.689 13.887 14.199 14.477 16.136 17.566 17.824 19.178 20.185 20.743 22.564 22.709 22.954 24.519 26.658

15633 8019 6385 22038 44027 20617 3501 30017 42776 17480 9037 19554 6585 11709 7498 24626 28657 14892 22060 41941 12459 38161 29003 total

0.18 0.09 0.08 0.26 0.52 0.24 0.04 0.35 0.50 0.21 0.11 0.23 0.08 0.14 0.09 0.29 0.34 0.18 0.26 0.50 0.15 0.45 0.34 10.46

2.875 4.480 5.076 7.142 7.212 7.543 7.700 8.016 8.924 11.353 11.978 13.364 15.084 17.125 20.383 24.746 25.687 26.971 26.968 29.479 34.494 39.832

27111 18888 21896 6770 6244 10287 2836 8362 8845 5845 10812 18528 8005 51339 53081 7851 23195 5238 5713 15844 18781 28987 total

0.32 0.22 0.26 0.08 0.07 0.12 0.Q3 0.10 0.10 0.07 0.13 0.22 0.09 0.61 0.63 0.09 0.27 0.06 0.07 0.19 0.22 0.34 4.19

5.006 8.631 9.011 13.163 14.700 16.586 16.678 19.871 25.224 25.317 39.034

69840 30445 37977 16574 14114 7683 9500 5542 17052 11157 38940

0.82 0.36 0.45 0.20 0.17 0.09 0.11 0.07 0.20 0.13 0.46

olefins 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32.

2-hexene, 2,5-dimethyl2-octene, (e) l-heptene, 2,4-dimethyll-heptene, 2,6-dimethyll-nonene 4-nonene 1,3-hexadiene, 3-ethyl-2-methyl, (z) 1-nonene, 2-ethyl1-decene 3-nonene, 2-methyl2-decene, (e) 2-hexadecene, 2,6,10, 14-tetramethyl2-decene, 8-methyl, (z) 2-undecene, (e) 2- dodecene, (e) 2-decene, 5-methyl, (z) undecene, 2-methyl 1-dodecene 1-dodecene, 2-methyl3-hexadecene, (z) 7- tetradecene, (z) 9-octadecene, (e) 1- tetradecene

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22.

cyclohexene cyclobutane, (L-methylethylidene) cyclohexene, L-methyll-cyclohexene, 1,3-dimethylcyclohexene, 3,5-dimethylcyclopentane, 1-methyl-2-(2-propenyl), trans cyclohexane, 1,1,3-trimethylcyclopentene, L-propyl cyclohexene, 4-ethylcyclohexane, propylcyclopentene, l-(2-methylpropyl) cyclohexane, L-methyl-3-propyl cyclohexane, butylcyclopropane, l-ethyl-2-heptylcyclopropane, nonylcyclododecane cyclooctacosane cyclohexane, 2-butyl-l, 1,3-trimethylcyclohexane, 1,2,3-trimethylcyclopentane, 3-hexyl-l, l-dimethylcyclotetradecane cyclotetracosane

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

toluene ethylbenzene benzene, 1,3-dimethylbenzene, l-ethyl-3-methylbenzene, 1,2,4-trimethylbenzene, 1-ethyl-2,3-dimethylbenzene, L-methyl-3-(1-methylethyl)benzene, (1, l-dimethyl propyl) naphthalene, 1,8-dimethylnaphthalene, 2,6-dimethylphenanthrene

naphthenes

aromatics

213


Article


name

R. time (min)

area

conc (%)

aromatics total

3.06

10.574 21.724 24.921

7403 10577 5391 total

0.09 0.12 0.06 0.27

51.619

53891

0.64

oxygenates 1. 2. 3.

3-nonen-l-ol, (E) 1-nonanol, 4,8-dimethyl1-decanol, 2-hexyl-

1.

octadecane, 1-iodo

alkyl halide

and >C30. The results are indicated in Table 11. It can be seen that, in the case of TDLP, the relative distributions of C6−C12, C13−C16, C17−C20, C21−C30, and >C30 hydrocarbons were 74, 20, 11, 9, and 4%, respectively. This shows that the proportion of the hydrocarbons linearly decreased with the increase in their molecular weight. In the case of the CDLP, the yields of the C6−C12 and C13−C16 range hydrocarbons were relatively changed whereas those of C17−C20, C21−C30, and >C30 remained unchanged. The yield of C6−C12 range hydrocarbons was found to be increased compared to the thermal run. The yield of C13−C16 range hydrocarbons was slightly increased. The relative proportions of C17−C20, C21−C30, and >C30 hydrocarbons in the CDLP were the same as in the case of the thermal run. The results indicate good activity of CA in generating products in the carbon number range of C6−C12 and C13−C16, which can be attributed to the activities shown by the Al and Si components of the catalyst.37,43 3.4. Fuel Properties. The fuels must meet certain specifications before being recommended for energy production or industrial use. Among these specifications, those for color, water content, stability upon storage, density, API gravity, total solids, viscosity, pour point, aniline point, diesel index, cetane number, calorific value, etc. are considered the most important ones. The fuel properties of the TDLP and that of CDLP were determined and compared with ASTM standard values for petroleum distillate fuels. The results are provided in Table 12. Both LPs were observed to be homogeneous with no phase distinction, which indicates no water contents. The samples were also found to be stable with no distinct changes in color and viscosity upon storage. The color of each fraction was compared with petroleum distillate fuels and found to be mostly yellowish on physical observation (naked eye) as well as colorimeter. The density of TDLP was found to be 0.91, while that of CDLP was 0.84 g/cm3. The density of CDLP is approaching close to the ASTM density of diesel oil. The density of typical petroleum derived diesel fuel/generic diesel fuel oil has been reported to be 0.836 g/cm3.44 The density data was used to calculate the API gravity and found to be 22 and 37 in the case of TDLP and CDLP, respectively. The diesel oil shows API gravity up to 38. The results show close agreement with the ASTM API gravity of diesel fuel, particularly in the case of CDLP. The viscosity values are found to fall in the range 1.25− 2.00 mm2/s and are comparable with the ASTM values for diesel fuel as well as the values reported in the literature.45,46 The pour point was found to be −5 °C in the case of TDLP compared to that of < −8 °C determined in the case of CDLP. The pour point of the light fractions occur around −6 °C. The values are comparable with the light fractions. The standard value of normal diesel fuel has been reported to be < −21 °C.

definite pore diameter and pore volume which might have assisted in the cyclization and aromatization. A generalized mechanism for the pyrolysis of hydrocarbon molecules during the catalytic process is given as follows: 1. Carbocation is formed by abstraction of proton from the hydrocarbon molecule over the catalyst.

2. β-Scission of the carbocation to form an olefin and another short chain carbocation.

3. H-transfer from a neutral molecule to the carbocation to form a stable molecule and another carbocation.

4. Cyclization of the carbocation to form cyclic hydrocarbons.

5. Aromatization of cyclic hydrocarbons by removal of hydrogen atoms.

3.3.2.3. Carbon Number Distribution. From the GC−MS results, the hydrocarbon molecules identified in the TDLP and CDLP can be grouped into different classes according to their carbon numbers, that is, C6−C12, C13−C16, C17−C20, C21−C30, 214


Article

Energy & Fuels Table 9. Individual Compounds Identified in Liquid Pyrolysates from Catalyzed Run S. No.

name

R. time (min)

area

conc (%)

3.155 4.869 5.136 6.190 8.723 8.806 10.215 10.893 11.502 12.688 12.917 13.994 14.749 16.061 16.413 17.282 17.401 19.483 19.748 20.614 20.932 22.263 22.870 23.772 23.913 24.129 24.675 26.132 26.870 27.933 28.43 28.515 30.060 32.562 33.3269 34.946 37.224 38.315 38.693 40.218 40.500 43.3262 45.991 49.353 53.379 55.767 56.075 57.152 59.691 64.069 67.278 70.359

794263 417626 156890 1012285 188943 206790 1066774 199946 224691 223101 225456 1183757 95353 140324 237881 242400 1345585 25889 224987 1259231 409502 342924 1287430 382802 146588 265273 1480683 289315 1759265 46980 120233 200803 2024419 178565 340627 2948156 539402 342682 329907 2289553 391907 315916 2188102 1795837 1426078 156101 253262 1054643 199936 520320 597479 173818 total

1.67 0.88 0.33 2.13 0.40 0.43 2.24 0.42 0.47 0.47 0.47 2.49 0.20 0.30 0.50 0.51 2.83 0.05 0.47 2.65 0.86 0.72 2.71 0.81 0.31 0.56 3.11 0.61 3.70 0.10 0.25 0.42 4.26 0.38 0.72 6.20 1.13 0.72 0.69 4.82 0.82 0.66 4.60 3.78 3.00 0.33 0.53 2.22 0.42 1.09 1.26 0.37 72.07

2.949 3.008 3.303 3.932 4.598 5.362

354633 535795 180609 201937 137425 402398

0.75 1.13 0.38 0.42 0.29 0.85

paraffins 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.

heptane octane, 2,5-dimethylheptane, 3-methyloctane octane, 4-methyl octane, 3-ethyl-2,7-dimethylnonane pentane, 3-ethyl-2,4-dimethyloctane, 2,6-dimethylnonane, 2-methylnonane, 3-methyldecane octane, 2,3,6-trimethylheptane, 2,5,5-trimethylnonane, 3,7-dimethylnonane, 2-methyl-3-methylene undecane undecane, 5-methylundecane, 3-methyldodecane undecane, 2,6-dimethylundecane, 3,9-dimethyltridecane tridecane, 6-methyltridecane, 4-methyltridecane, 3-methyltetradecane tetradecane, 3-methylpentadecane decane, 5-propylundecane, 2-cyclohexylpentadecane, 4-methylhexadecane dodecane, 2,6,l l-trimethylheptadecane, 2,6,10,14-tetramethyl heptadecane heptadecane, 8-methylheptadecane, 2-methylheptadecane, 3-methyloctadecane tritetracontane tetratriacontane nonadecane eicosane henicosane hentriacontane pentatriacontane docosane octacosane tetracosane pentacosane hexacosane

1. 2. 3. 4. 5. 6.

1-hexene, 2-methyll-heptene 2-heptene, (E) l-hexene, 2,3-dimethyl1-octene, 3,7-dimethyl2-pentene, 2,3,4-trimethyl-

olefins

215


Article


name

R. time (min)

area

conc (%)

5.663 5.857 6.748 7.788 8.173 9.881 10.445 10.730 13.455 13.688 13.884 14.197 14.475 16.139 17.568 17.827 18.779 20.191 20.749 22.571 22.715 23.139 24.529 26.678

442160 469370 96741 27598 180646 430854 265966 117862 235300 387447 245050 129491 178143 58165 156425 100626 34472 201354 157185 158925 29462 90884 270638 192279 total

0.93 0.99 0.20 0.06 0.38 0.91 0.56 0.25 0.49 0.81 0.52 0.27 0.37 0.12 0.33 0.21 0.07 0.42 0.33 0.33 0.62 0.19 0.57 0.40 14.15

2.851 4.434 5.028 6.458 7.176 7.508 7.665 70984 11.339 11.966 13.358 15.082 17.131 20.390 24.757 25.703 26.738 26.989 29.860 34.293 39.871

176447 259852 263691 194856 83827 134235 30127 101723 80263 146276 209055 102297 46344 461528 94975 200531 132619 71975 57554 4642 92476 total

0.37 0.55 0.55 0.41 0.18 0.28 0.06 0.21 0.17 0.31 0.44 0.22 0.97 0.97 0.20 0.42 0.28 0.15 0.12 0.01 0.19 7.06

10.560 20.280 24.935

85892 305903 81654 total

0.18 0.64 0.17 0.99

4.956 8.602 9.036 13.156 14.700 16.592

723712 338905 182828 235921 193187 128133

1.52 0.71 0.40 0.50 0.41 0.27

olefins 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30.

1-heptene, 2-methyll-octene 2-octene, (E) l-heptene, 2,4-dimethyl. 1-heptene, 2,6-dimethyl1-nonene 4-nonene 2-nonene 1-nonene, 2-methyl1-decene 3-nonene, 2-methyl2-decene, (E) 2-hexadecene, 2,6,10, l4-tetramethyl2-decene, 8-methyl-, (Z) 2-undecene, (E) 2-dodecene, (E) 2-decene, 5-methyl, (Z) l-undecene, 2-methyl1-dodecene 1-dodecene, 2-methyl3-hexadecene, (Z) 7-tetradecene, (Z) 9-octadecene, (E) 1-tetradecene

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21.

cyclohexene cyclobutane, (L-methylethylidene) cyclohexene, 1-methyl cyclopropane, (2,2-dimethyl propyl idene) l-cyclohexene, 1,3-dimethyl cyclopentane, 1-methy1-2-(2-propenyl), trans cyclohexane, 1,1,3-trimethylcyclopentene, L-propyl cyclohexane, propyl cyclopentene, l-(2-methylpropyl) cyclohexane, 1-methyl-3-propylcyclohexane, butylcyclopropane, l-ethyl-2-heptylcyclopropane, nonylcyclododecane cyclooctacosane cyclohexane, 2-butyl-1,1,3-trimethylcyclohexane, 1,2,3-trimethylcyclopentane, 3-hexyl-l, l-dimethylcyclotetradecane cyclotetracosane

1. 2. 3.

3-nonen-1-ol, (E) indene, 2,3-dihydro-l,2-dimethyl1-decanol, 2-hexyl-

1. 2. 3. 4. 5. 6.

toluene ethylbenzene benzene, 1,3-dimethylbenzene, l-ethyl-3-methylbenzene, 1,2,4-trimethylbenzene, l-ethyl-2,3-dimethyl-

naphthenes

oxygenates

aromatics

216


Article


name

R. time (min)

area

conc (%)

16.683 19.879 25.242 25.334 39.067

162094 95672 194170 126891 187907 total

0.34 0.20 0.41 0.27 0.40 5.43

51.633

122670

0.26

aromatics 7. 8. 9. 10. 11.

benzene, 1-methyl-3(L-methylethyl) benzene, (1,l-dimethylpropyl) naphthalene, 1,8-dimethylnaphthalene, 2,6-dimethylphenanthrene

1.

octadecane, 1-iodo

alkyl halide

calculated. The DI was found to be within the range 49−55 and conforms to the values reported for diesel fuels. The results were used to calculate the cetane number (CN) by the empirical expression reported elsewhere.49,50 The CN values of both LPs were found to within the range 45−58. The values fall within the range reported for commercial diesel fuels. The calorific values of TDLP and CDLP were 43 and 44 MJ/kg and indicate substantial heating value required for commercial heating applications.

Table 10. Hydrocarbon Group Types Distribution in Liquid Pyrolysates from Thermal and Catalyzed Runs conc (%) hydrocarbon group type

thermal run

catalyzed run

paraffins olefins maphthenes aromatics oxygenates alkyl halides

81.30 10.46 4.19 4.19 0.27 0.64

72.07 14.15 7.06 5.43 0.99 0.26

4. CONCLUSIONS

Table 11. Carbon Number Distribution in Liquid Pyrolysates from Thermal and Catalyzed Runs conc (%) carbon range product type

thermal run

catalyzed run

C6−C12 C13−C16 C17−C20 C21−C30 >C30 total

62.70 16.95 9.32 7.63 3.39 99.99

61.90 17.80 9.30 7.60 3.40 100.00

Table 12. Fuel Properties of the Liquid Pyrolysates from Thermal and Catalyzed Runs fuel property density @ 15 °C (g/cm3) specific gravity API gravity @ 60 °F ash (% wt) kinematic viscosity @ 40 °C (mm2/s) pour point (°C) aniline point (°F) diesel index cetane number calorific value (MJ/kg) a

thermal run

catalyzed run

standard ASTM values

0.91 0.92 22 0.058 2.0

0.84 0.84 37 B.D.a 01.25

0.85 0.85 39−44 (typical 40) 0.01 1.3−4.1

−5 188.6 (87 °C) 41 45.30 39

> −8 181.4 (83 °C) 67 58.24 44

−35 to −15 154

■

• Experimental parameters (temperature, SLO/PBC, residence time) gave rise to a significant change, while the catalyst gave a marginal change in the product yields. • The catalyst used did not cause a significant increase in the yield of the obtained liquid products in comparison with the thermal run; however, it demonstrated a great influence on LPs composition in terms of paraffins, olefins, naphthenes, and aromatics and gave an improved amount of cyclic structures with a corresponding decrease in open paraffinic structures. • The derived liquid products contained various light, middle, and heavy hydrocarbons with good distribution of paraffins, olefins, naphthenes, and aromatics. • All of the fuel properties met best with the diesel fuel specification, particularly in the case of CDLP; hence, it could be used as a substitute to diesel fuel in commercial applications.

AUTHOR INFORMATION

Corresponding Author

*Telephone: +92-91-9216652. Fax: +92-91-9216652. E-mail: [email protected]. Notes

The authors declare no competing financial interest.

■

47 40−55 42−44

REFERENCES

(1) Hani, F. B.; Al-Wedyan, H. Afri. J. Biotechnol. 2013, 10, 1050. (2) Abro, R.; Chen, X.; Harijan, K.; Dhakan, Z. A.; Ammar, M. A Comparative Study of Recycling of Used Engine Oil Using Extraction by Composite Solvent, Single Solvent, and Acid Treatment Methods. ISRN Chem. Eng. 2013, 95258910.1155/2013/952589 (3) Williams, P. T. Waste Treatment and Disposal; John Wiley & Sons: 2013. (4) Nouri, J.; Nouri, N.; Moeeni, M. Int. J. Environ. Sci. Technol. 2012, 9, 417. (5) Gaidajis, G.; Angelakoglou, K.; Botsaris, P. N.; Filippidou, F. Resourc.Conser.Recycl. 2011, 55, 986. (6) Mohammed, R. R.; Ibrahim, I. A.; Taha, A. H.; McKay, G. Chem. Eng. J. 2013, 220, 343.

B.D: below detection.

According to the ASTM D611 method, the aniline point is used to evaluate the degree of aromaticity of a fuel sample.47,48 Further, it is a useful parameter in calculation of heat of combustion, diesel index, hydrogen content, and smoke point of petroleum fuels. The aniline points of the LPs were found fall within the range 78−83 °C; the values are a bit higher than the ASTM values of diesel fuels. The typical diesel performance properties, such as diesel index and cetane number, were also 217


Article

Energy & Fuels (7) Katiyar, V.; Husain, S. A. T. T. A. R. Int. J. Chem. Sci. 2010, 8, 1999. (8) Kupareva, A.; Mäki-Arvela, P.; Murzin, D. Y. J. Chem. Technol. Biotechnol. 2013, 88, 1780. (9) Owolabi, R. U.; Alabi, K. A.; Oke, O. B. Fountain J. Natural Appl. Sci. 2013, 2, 11. (10) Usman, M. A.; Kayode-Sote, O. G. Petrol. Coal 2011, 53, 159. (11) Betton, C. I. Lubricants and their environmental impact. In Chemistry and technology of lubricants; Springer: Netherlands, 2010; pp 435−457. (12) Jafari, A. J.; Hassanpour, M. Resour.Conserv.Recy. 2015, 103, 179. (13) Fumoto, E.; Tago, T.; Tsuji, T.; Masuda, T. Energy Fuels 2004, 18, 1770. (14) Naima, K.; Liazid, A. J. Petrol. Technol. Alternative Fuels 2013, 4, 30. (15) Arpa, O.; Yumrutas, R.; Demirbas, A. Appl. Energy 2010, 87, 122. (16) Demirbas, A. Energy Sources, Part A 2008, 30, 1433. (17) Bhaskar, T.; Uddin, M. A.; Muto, A.; Sakata, Y.; Omura, Y.; Kimura, K.; Kawakami, Y. Fuel 2004, 83, 9. (18) Ö ztop, H. F.; Varol, Y.; Altun, Ş.; Firat, M. Energy Sources, Part A 2014, 36, 1468. (19) Permsubscul, A.; Vitidsant, T.; Damronglerd, S. Korean J. Chem. Eng. 2007, 24, 37. (20) Balat, M. Diesel-like fuel obtained by catalytic pyrolysis of waste engine oil. Energy Explor. Exploit. 2008, 26, 197. (21) Trisunaryanti, W.; Purwono, S.; Putranto, A. Indonesian J. Chem. 2010, 8, 342. (22) Na, C. Turk. J. Chem. 1999, 23, 309. (23) Fernandez, R.; Martirena, F.; Scrivener, K. L. Cem. Concr. Res. 2011, 41, 113. (24) Moore, D. M; Reynolds, R. C. X-ray Diffraction and the Identification and Analysis of Clay Minerals; Oxford University Press: New York, 1989. (25) Aroke, U. O.; Abdulkarim, A.; Ogubunka, R. O. ATBU J. Environ. Technol. 2013, 6 (1), 42−53. (26) Pavia, D.; Lampman, G.; Kriz, G.; Vyvyan, J. Introduction to Spectroscopy. Cengage Learning 2014. (27) Gürses, A.; Karaca, S.; Doğar, C.; Bayrak, R.; Açıkyıldız, M.; Yalçın, M. J. Colloid Interface Sci. 2004, 269, 310. (28) Rehman, M. S. U.; Munir, M.; Ashfaq, M.; Rashid, N.; Nazar, M. F.; Danish, M.; Han, J. I. Chem. Eng. J. 2013, 228, 54. (29) Lam, S. S.; Russell, A. D.; Lee, C. L.; Chase, H. A. Fuel 2012, 92, 327. (30) Sınağ, A.; Gülbay, S.; Uskan, B.; Uçar, S.; Ö zgürler, S. B. J. Hazard. Mater. 2010, 173, 420. (31) Kim, S. S.; Kim, S. H. Fuel 2000, 79, 1943. (32) Eschner, M. S.; Gröger, T. M.; Horvath, T.; Gonin, M.; Zimmermann, R. Anal. Chem. 2011, 83, 3865. (33) Song, C.; Lai, W. C.; Reddy, K. M.; Wei, B. Analytical Advances for Hydrocarbon Research, Part of the series Modern Analytical Chemistry; Springer: 2003; pp 147−210. (34) Bae, E.; Na, J. G.; Chung, S. H.; Kim, H. S.; Kim, S. Energy Fuels 2010, 24, 2563. (35) Benassi, M.; Berisha, A.; Romão, W.; Babayev, E.; Römpp, A.; Spengler, B. Rapid Commun. Mass Spectrom. 2013, 27, 825. (36) Lu, J.; Zhao, Z.; Xu, C.; Duan, A.; Wang, X.; Zhang, P. J. Porous Mater. 2008, 15, 213. (37) Hwang, S.; Lee, J.; Park, S.; Park, D. R.; Jung, J. C.; Lee, S. B.; Song, I. K. Catal. Lett. 2009, 129, 163. (38) Rahimi, N.; Karimzadeh, R. Appl. Catal., A 2011, 398, 1. (39) Huo, Q.; Dou, T.; Zhao, Z.; Pan, H. Appl. Catal., A 2010, 381, 101. (40) Samia, A. H.; Mohammed, M. S.; Faramawy, S.; Ahmed, S. A.; Ahmed, H. B. Egypt. J. Pet. 2015, 24, 163. (41) Katikaneni, S. P.; Adjaye, J. D.; Bakhshi, N. N. Can. J. Chem. Eng. 1995, 73, 484. (42) Idem, R. O.; Katikaneni, S. P.; Bakhshi, N. N. Fuel Process. Technol. 1997, 51, 101.

(43) Bari Siddiqui, M. A.; Aitani, A. M.; Saeed, M. R.; Al-Khattaf, S. Top. Catal. 2010, 53, 1387. (44) Speight, J. G. Handbook of petroleum product analysis; John Wiley & Sons: 2015. (45) Yasin, G.; Bhanger, M. I.; Ansari, T. M.; Naqvi, S. M. S. R.; Talpur, F. N. J. Pet. Technol. Altern. Fuels 2012, 3, 29. (46) Martínez, J. D.; Lapuerta, M.; García-Contreras, R.; Murillo, R.; García, T. Energy Fuels 2013, 27, 3296. (47) Albahri, T. A.;Riazi, M. R.;Alqattan, A. A. Octane number and aniline point of petroleum fuels. In 224th ACS National Meeting, 2002 (pp 710−711). (48) Albahri, T. A. J. Mol. Liq. 2012, 174, 80. (49) Gürü, M.; Karakaya, U.; Altıparmak, D.; Alıcılar, A. Energy Convers. Manage. 2002, 43, 1021. (50) Haldar, S. K.; Ghosh, B. B.; Nag, A. Biomass Bioenergy 2009, 33, 1013.

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