Experimental Investigation on Thermocatalytic Pyrolysis of HDPE

Subscriber access provided by - Access paid by the | UCSB Libraries

Article

Experimental investigation on thermo-catalytic pyrolysis of HDPE plastic waste and the effects of its liquid yield over the performance, emission and combustion characteristics of CI engine. Narayanan Karisathan Sundararajan, and Anand Ramachandran Bhagavathi Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.6b00407 • Publication Date (Web): 02 Jun 2016 Downloaded from http://pubs.acs.org on June 9, 2016

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

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

Page 1 of 50

Energy & Fuels

1 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

Experimental investigation on thermo-catalytic pyrolysis of HDPE plastic waste and the effects of its liquid yield over the performance, emission and combustion characteristics of CI engine.

Narayanan Karisathan Sundararajan and Anand Ramachandran Bhagavathi Department of Mechanical Engineering *

National Institute of Technology, Tiruchirappalli Tamil Nadu – 620 015, INDIA.

*

Corresponding Author, E-mail: [email protected]

ACS Paragon Plus Environment

Energy & Fuels

Page 2 of 50

2 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

Abstract An experimental investigation was carried out to study two process parameters of thermo catalytic pyrolysis of high density polyethylene (HDPE) plastic waste and the liquid yield of pyrolysis (plastic oil) was analyzed over its working characteristics in a direct injection compression ignition (DICI) engine. A series of pyrolysis experiments with four different heating rates (5, 10, 15, 20 °C/min) were performed in identical environments with the objective of analyzing the heating rate and residence time on end products. It was found that the liquid yield was maximum at the heating rate of 10 °C/min and the residence time decreases with increase in heating rate due to variation of reaction kinetics at different heating rates. The characterization of the plastic oil revealed that the major constituents belong to alkene, alkane and alcohol functional groups and totally ninety six fuel range hydrocarbons were present ranging from C5 to C28 and the other thermo-physical properties were comparable with that of petro-diesel. The plastic oil was tested for its working characteristics as main fuel in a DICI engine with the aim of analyzing the effect of chemical constituents present in it and the experimental results showed that no hardware modifications were required for employing the plastic oil in place of petro-diesel in DICI engine. The brake thermal efficiency and specific fuel consumption were higher by 4.53 % and 7.16 % respectively for plastic oil than petro-diesel due to the presence of alcohols, alkenes and constituents with higher molecular weight hydrocarbons in the plastic oil. A reduction of 25.9 % in ignition delay was evidenced with plastic oil than petro-diesel at rated load which might possibly be due to the structural influence i.e. absence of aromatics with ring type molecular structure in plastic oil.

Keywords: plastic waste, thermo-catalytic pyrolysis, bentonite, fuel range hydrocarbons.


Page 3 of 50

Energy & Fuels

3 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

1. Introduction Ever increasing plastic production since 1950’s, managed to saturate the world with plastic waste products. Hence the plastic waste accumulation is also inevitable and increasing day by day. The plastic waste (PW) poses a major threat to human kind due to its non-biodegradability that leads to adverse interaction with environmental system. Increased population with their sophisticated life style has resulted in rampant increase in energy requirement and subsequent environmental pollution. This necessitates the exploration of every means for exploiting the energy in a sustainable development means and taking remediation for anthropogenic damage to ecosystems. Since plastic mainly constitutes hydrocarbons, they become a good source of energy and there is a possibility of energy recovery during disposal. There are many other techniques available for PW disposal like controlled incineration, burning in kilns, and lands filling. However these ways are having their own inherent demerits like environmental pollution, inefficient thermal recovery and wastage of useful land. Hence deriving fuel from plastic waste in an efficient manner shall be the best thought to dispose and achieve a sustainable environment which can reduce the fossil fuel depletion by using them as alternate fuel in internal combustion engines. A potential solution for this thought is energy recovery by pyrolytic thermal decomposition of plastic waste and use in appropriate energy transformers, particularly in DICI engines, which are the focused objective of many researchers.1,2 Pyrolysis process of plastic basically comprises of thermo-chemical decomposition at elevated temperature in the absence of oxygen. During pyrolysis, plastics undergo chemical change involving cracking phenomena, which basically constitute three major types namely random cracking, chain strip cracking, and end chain cracking.3 Further, depending on the process like slow and flash pyrolysis, a number of reactor systems have been developed such as rotary kiln with fixed vertical / horizontal furnaces those equipped with rotating / moving blades (slow pyrolysis), continuous screw kiln type, fluidized bed, entrained flow reactor, and vortex ablative reactor


Energy & Fuels

Page 4 of 50

4 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

(flash pyrolysis).4 In addition, microwave pyrolysis5,6 and plasma pyrolysis7 are in incipient stage of their development. Out of these, fixed batch type reactor with conventional conductive heating has been used by many researchers because of its simple design and easy instrumentation control. With respect to the kinetics of reactions in pyrolysis, high reflux and wide end product constituents are the bottlenecks. Hence to tackle these problems, catalysts are solutions which enable plastic cracking to be performed at lesser heat input, and the product constitution can be controlled by a right selection of the catalyst to be used.8 The catalyst bears surface loaded acid sites9 and this can be achieved through activation process that can be done with strong acids and bases. The major end product of controlled pyrolysis of plastics constitutes fuel range hydrocarbon liquid, wax, gaseous products and residues. However, as far as the pyrolysis is concerned a series of pyrolysis parameters (heating rate, residence time, catalytic loading, catalytic reaction), type of pyrolysis (Slow, medium and Flash) and quality of polymer used decide the end product recovery. In a recent work by Syamsiro et al.,10 the authors investigated catalytic pyrolysis of three feedstocks namely waste PE bag 1, waste PE bag 2 (both of them constitute mostly light density polyethylene) and HDPE plastic waste by using natural zeolite and commercial Y-zeolite catalysts to study the effect of catalyst over end yield and reported that feedstock influence much in yield products. Particularly HDPE plastic waste yielded more oil output with heavy oil fractions with natural zeolite catalyst than Y-zeolite catalysts. Omar et al.,11 studied the effect of carbon nano tubes (CNTs) on the pyrolysis of high density polyethylene (PE) and polypropylene (PP) matrices by using both kinetic thermo gravimetric analyses (TGA) under non-isothermal conditions and a fixed-bed reactor under isothermal conditions. Authors confirmed that high condensable (C9–C40) yield resulted around 450 °C. The authors further reported that CNTs showed less reaction on polymer and a lower both condensable and gas yields for PE-CNT composites than pure PE matrix.


Page 5 of 50

Energy & Fuels

5 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

Though works were done on the conversion of plastic waste, but not substantially, investigations to establish the role of particular type of polymer waste on end product constitution at defined pyrolysis conditions, their possible chemical reactions involved during pyrolysis and chemical constituents present in the liquid end product recovery on performance, emission and combustion characteristics in CI engine were rarely done. There are works with the corollary that explain the interdependence of engine operating characteristics with the variations in operating parameters like injection pressure, compression ratio, speed of the engine and combustion conditions, which obviously play role in deciding the feasibility of commercial use of the fuel but their adaptation in the engine can be possible by latest technological improvements in mechatronix engineering only if the chemistry of the fuel is better understood. Hence inspired by this, in this work, by fixing a polymer waste, catalyst, their loading ratio and a type of pyrolysis, two objectives were taken; 1) Analyzing the effects of two pyrolysis parameter (heating rate and residence time) on end products, 2) Analyzing the role of chemical constituents present in end liquid product of pyrolysis on performance, emission and combustion characteristics of CI engine while using it as a fuel. 2. Experimental section 2.1. Materials Shredded High Density Polyethylene (HDPE) plastic waste (from bottles of Blow molding grade, pigmented and bearing resin identification code (RIC) ‘2’ within recycling triangle) obtained from local vendors, commercially available bentonite clay powder, Laboratory Analysis Grade NH4Cl (Assay > 99%), and guaranteed reagent grade NaOH pellets (Supplier: Merck Specialties Private Limited, INDIA), were used for production of plastic oil. The physical and rheological properties of HDPE plastic waste, (Density, melt flow index, melting point), the most pertinent to the pyrolysis of plastic waste were characterized and mentioned in Table 1.


Energy & Fuels

Page 6 of 50

6 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

2.2.

Preparation of catalyst

The commercially available bentonite was processed based on the procedure adopted by Jeong-Geol Na et al.8 and employed in the present investigation. The experimental setup consists of a variable speed stirrer motor for stirring the catalyst mixed chemical solution, resistant temperature detector for detecting the temperature of the catalyst mixed alkaline solution, a temperature controller for controlling the temperature of the catalyst mixed chemical solution, a relay switch to protect the temperature controller and switching during temperature control and a heater for heating the catalyst mixed chemical solution. This is shown in Figure 1. About 320 g of raw bentonite was dissolved in one liter of de-ionized water and was allowed to settle down for one hour to separate the dusts if any. Then the filtrate was removed and dried at a temperature of 100 °C for 3 hours. Then 200 g of dried product was mixed with 300 g of NaOH and the mixture was dissolved in de-ionized water with a solid/liquid ratio of 0.2(w/w), followed by an activation process that include agitation and heating up to 80 ºC for 8 hours. The solid phase of resulting material was separated by filtration and washed with NH4Cl having a molarity of 1 until a pH value of 7 was reached. Subsequently it was calcined at 500 °C for 2 hours in a muffle furnace. The synthesized catalyst was stored in polyethylene bags for further use. 2.3.

Properties and characterization of Raw materials Scanning Electron Microscopy - Energy dispersive X-Ray spectroscopy (SEM-EDS) analyses of

catalyst were performed to investigate the morphology and chemical composition of bentonite and plastic waste. The SEM observation was carried out for activated bentonite in Hitachi S-3000H system with the Resolution of 3.5 nm @ 25 kV high vacuum mode, magnification sensitive area of 30 mm² and a energy resolution of < 145 eV at 300000 cps (count rate Cu > 400,000 cps) to acquire a set of X-ray maps at 1 millisecond dwell time per pixel acquisition for approximately one million counts and the


Page 7 of 50

Energy & Fuels

7 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

obtained output image is shown in Figure 2. For elemental analyses of raw bentonite and catalyst, EDS (make BRUKER) was used, in which elemental mapping data were obtained at an accelerating voltage of 10.0 kV. Elementar, Model: Vario EL III instrument was used to analyze the CHNS and O composition of HDPE waste plastic. The results obtained through EDS and CHNS and O elemental analyzer are mentioned in Table 2. Thermo gravimetric analysis (TGA) (Instrument details: Universal, V4.7A TA Instruments, model SDT Q600 V20.9) was performed to investigate the phase transition, endothermic heat requirement and degradation temperature of the HDPE plastic waste with and without catalyst and the tests were performed with the heating rate of 10 °C/min from room temperature to 600/800 °C. Particle size analysis was performed to investigate physical changes (size) that take place in bentonite before and after activation by Zeta particle size analyzer that works by Dynamic Light Scattering (DLS) principle (Instrument details: Malvern, Zetasizer Ver. 6.20, Serial Number: MAL1054413) with water as dispersant having refractory index of 1.33 and viscosity of 0.8872 cP (Instrument settings: measurement position = 4.65 mm, polydispersity index (PdI) of 1 and Attenuator position = 6). 2.4.

Catalytic Pyrolysis experiments The physical and rheological properties (density, melting point and melt-flow index) of the

plastic waste (Table 1), the role in reaction kinetics of the catalyst and size, morphology were confirmed through characterization before the actual production process. The experimental setup for pyrolysis that was used by Narayanan et al.12 was adopted for the present investigation. The setup consisted of a stainless steel retort, furnace, condenser unit, simple flare, nitrogen supply, liquefied petroleum gas (LPG) flow meter, pressure regulator and industrial burner. The main intend of this part of experimentation was to examine the effect of two pyrolysis parameters namely heating rate and


Energy & Fuels

Page 8 of 50

8 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

residence time, their interdependency on the end products by conducting the experiments at four heating rates (5, 10, 20, 25 °C/min). The pyrolysis process was performed in a batch type fixed rector. Two kilograms of cleaned and dried feedstock plastic of 5 to 8 mm in size and catalyst, in a loading ratio of 10:1 (Plastic: catalyst), were used as raw materials in all four experiments. Shredding to the size was made to improve the packing density inside the retort and to have uniform and better heat flow around the feed stock. Slow pyrolysis was adopted during all the four different heating rates and the heating rate was controlled by the LPG flow meter, pressure regulator, and adjustable type naturally aspirated industrial burner. A constant heating rate at the rate of 5, 10, 20 and 25 °C/min were achieved by controlling the LPG flow at the rate of 0.5, 1.0, 2.0 and 2.5m3/h during the four experiments, respectively. The temperatures were measured with the help of k-type thermocouples provided at the outer wall and inner space of the retort. In all experiments, identical pyrolysis environment inside the retort was maintained by passing nitrogen at the rate of 20 ml/min at atmospheric pressure. The optimum liquid product was obtained in a temperature range of 475 to 525 °C at a heating rate of 10 °C/min and the corresponding time of complete decomposition (retention time) of two kg of plastic was found to be 95 minutes. The liquid products obtained at optimum liquid yield conditions were considered for the further analyses. Liquid, waxy product yield and residue were weighed and the gaseous yields were calculated by adopting the mass balance. Three test runs were conducted at each heating rate to check the consistency of results and the values were found within 3 % variation. The flammable gaseous products evolved during the process were burnt through a simple flare. 2.5.

Analysis of plastic oil The plastic oil was subjected to various characterization techniques namely, Fourier Transform

Infrared (FTIR) spectroscopy analysis, C, H, N, S and O elemental analysis and Gas Chromatography Mass Spectrography (GC-MS) studies. The analyses for determining the properties of the plastic oil


Page 9 of 50

Energy & Fuels

9 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

were performed as per American Society for Testing and Materials (ASTM) standards and its comparison with that of Petro diesel are mentioned in Table 3. Elemental composition analyzer (Elementar, Model: Vario EL III, Accuracy = ± 0.05 %) was used to determine C, H, N, S and O content in the plastic oil by employing helium as the carrier gas with the lower detection limit of 0.1 µg for N, 0.5 µg for C, H, and S and the analysis time was around 10 to14 minutes. The plastic oil was subjected to FTIR (Make: Perkin Elmer, Spectrum Version 10.03.09, model - Spectrum Two) spectrometry study to identify the basic functional groups. The obtained spectrograph (Figure 3) shows the transmittance spectrum in percentage incident intensity along the span of wave numbers 4000 to 400 cm-1. The instrument is tuned to resolution four and four scans were done. The results are given Table 4. GC-MS analysis was performed to investigate the total compounds present in plastic oil (Instrument details: Perkin Elmer, model: Clarus 500 with Turbo mass, ver. 5.2.0 Software, Elite-5MS capillary column of length of 30 m and internal diameter of 250µm, split inlet type injector, instrument settings: Oven Program was set at 40°C [10min] @ 7 °C/min to 200 ºC [5min] @ 8 °C/min to 250 °C [3min], vaporizing temperature of injector = 250 °C with split ratio of 1:10.). In the measurement chain, MS part of the instrument used an electron impact ionization technique with 70 eV energy. A sample of 1.0 µl was injected and for the results, the library model NIST 2005 was referred. The spectrum is shown in Figure 4 and the results are summarized and given in Table 5. 2.6.

Experiment on working characteristic of CI engine The engine experimental setup used by Sadhik Basha and Anand13 was utilized for this

investigation. The setup comprised a constant speed four stroke DICI engine, loading device (alternator), data acquisition system and exhaust gas analyzers (AVL Di-gas analyzer and AVL smoke meter) to measure the level of unburned hydrocarbons (UHC), NOx, CO, CO2, and the smoke opacity while exhaust gas temperature (EGT) of engine was measured by using a calibrated thermocouple. The


Energy & Fuels

Page 10 of 50

10 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

schematic layout of the experimental setup is shown in Figure 5 and the technical specification of the engine and the data acquisition system are mentioned in Table 6. The engine was initially warmed up until the engine oil temperature reached approximately 100 °C. All the test runs are carried out by starting and warming up the engine with neat diesel and then switching over the fuel to plastic oil fuel. At the end of the test, the engine is again set to run with the petro- diesel to wash out the traces of the plastic oil in the fuel line and the injection system. The operating characteristics of both plastic oil and petro-diesel separately without any blending with each other were obtained at different loads for a constant speed of 1500 rpm. The levels of UHC, NOx, CO, and CO2 in the exhaust gases were measured and the performance characteristics data were recorded when the engine and exhaust temperatures reached equilibrium state. The experiments were performed thrice at identical conditions and found that readings were consistent. All the experimental data were recorded and processed with the help of the data acquisition system to compare the working characteristics of plastic oil and petro-diesel. The engine parameters, such as fuel injection timing (26 °crank angle bTDC) and pressure (215 bar), were maintained same for both the fuels. 2.7. Uncertainty analysis Instrument, observation reading, ambient and calibration can incorporate certain amount of errors and uncertainties in the experiments. Hence to validate the accuracy of experiment measurements, the uncertainty analysis on measured and estimated values was carried using the method described by Holman.14 The percentage uncertainty of brake thermal efficiency was calculated from percentage uncertainties of instruments and the results are given in Table 7.

3.

Results and discussion

Micro graphical image (Figure 2) obtained from the SEM of activated bentonite revealed the presence of large particles that appeared to have been formed by several flaky particles stacked together in the form


Page 11 of 50

Energy & Fuels

11 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

of tubular agglomerates during activation. Carbon impurities were not predominantly observed. The EDS analysis of raw bentonite (RB) clay powder and activated bentonite (AB) powder was conducted to ascertain the constituents and change in Si/Al ratio due to effects of the activation process which are the indicators of catalytic qualities relating to acid sites 3. From the results (Table 2) it is revealed that bentonite clay was calcium based. The Si/Al ratio of raw bentonite and activated bentonite were 4.64 and 8.56 respectively. The plausible explanations for the increase in Si/Al ratio is the leaching of Al, Mg and Fe, cations in octahedral and inter layers of bentonite due to hydrolysis during chemical activation, which is responsible for the increase in acid strength of Bronsted acid sites.15, 16 The results evidence the leaching of Mg and Fe to a value of 84.99 % and 59.64 % respectively. From the EDS analysis it is observed that, there was an increase in Ca by 3.5% after activation. This could be due to addition of Ca formed over the surface of the glass ware containing alkaline earth (7-9 % CaO) (used for activation) by corrosion on reaction with strong alkali (NaOH)17. To avoid this, during activation of catalyst very high alkaline resistant glass ware or borosilicate glass ware having no alkaline earth (like CaO) constituent may be used. However the catalytic quality was not found to be affected which was confirmed through the Thermo gravimetry - Differential Scanning Calorimetry (TG-DSC) analysis of HDPE plastic waste carried out with and without catalyst. However, the substitution of Al3+ in tetrahedral layers during activation was responsible for formation of Lewis acid cites. The results revealed that the bentonite had acquired the catalytic quality parameters during activation. By using DLS technique, zeta particle average size values of RB and AB were found as 3139 and 4122 nm, respectively. From these values it is evident that marginal swelling of bentonite had taken place during activation. Since it was calcium based, swelling was not predominant and this similarity was observed in the work of Kamal et al.18


Energy & Fuels

Page 12 of 50

12 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

During thermal analyses, all three thermo grams; Thermo gravimetric (TG), DSC, and Differential Thermogravimetric (DT) were obtained. DT and TG curves showed insignificant reduction in phase transition (2.63 °C) and degradation (0.04 °C) temperatures for waste HDPE plastic with catalyst when compared with that of without catalyst. From the results of the DSC endotherms (Figure 6), it is evident that a significant reduction in heat flow during reaction, especially at two distinct phase transitions for plastic with catalyst when compared with that of pure plastic, were evidenced during DSC analysis. Since area under the dip of DSC curves is a measure of latent heat of melting and it indicates that the catalyst has played a major role in reduction of activation energy required for polymer phase transition and degradation (reduction in heat flow of 27.56% at first transition temperature and 65.60 % at final degradation temperature). Not only at phase transitions, but also throughout the process, the endothermic curves of polymer with catalyst are well above that of pure polymer. This shows the possibility for energy efficient way of waste to energy recovery. It was found later in the pyrolysis experiments that the degradation temperature was around 470 °C, which was comparable with TGA analysis results. From TG-DSC analysis of the present work, it found that the first peak (corresponding to melting point) is at 138.12 °C and the second peak (corresponding to cracking temperature) is at 476.44 °C with the HDPE plastic waste (melt flow index = 7 g/10min) at the heating rate of 10 °C/min and degradation temperature for HDPE waste plastic (without catalyst) at which the maximum weight loss has taken place is at a temperature of 498.4 °C at the heating rate of 10 °C/min (Figure 7). This is also in line with the report of Sachin Kumar 19, where the maximum weight loss has taken place at a temperature of 465 °C at the heating rate of 10 °C/min and the melting point of 137.46 °C was reported through DSC studies for the HDPE plastic waste (without catalyst) with the average melt flow index between 0.2 -15 g/10min at the heating rate of 10 °C/min This is shown in Figure 8.


Page 13 of 50

Energy & Fuels

13 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

During FTIR spectrometry analysis, on interaction of infrared spectrum with the plastic oil, different assignments of IR radiation like stretching, bending and vibration were observed corresponding to chemical bond associated with the oil in a specific wave length range. The results of FTIR analysis (Table 4) of plastic oil reveal that the most of the functional groups belong to alkyl, alkenyl, and hydroxyl. The interpretations of spectra assignments were referred with the report by Coats20 and are in line with the observations by Sarker et al.21 The results of elemental analysis for C, H, N, S and O of plastic oil and that of petro-diesel as referred from the report of earlier work22 are mentioned in Table 2. The carbon and hydrogen contents in the plastic oil and petro-diesel are almost same. For obvious reasons it is reasonable to conclude that the absence of nitrogen and sulphur can improve the quality of plastic oil as a fuel when compared to petro-diesel (as per ASTM D 975-07 for petro-diesel shown in Table 3). The results of GC-MS analyses of plastic oil (Table 6) reveal that out of ninety six compounds present, n-aliphatic alkanes (paraffin), alkenes (olefin), cycloalkanes and alcohols constituted the most. No compounds of nitrogen were identified and this is agreeable with the results of FTIR analysis. The carbon chain distribution, from GC-MS analyses, of plastic oil are C7, C9-C12 constitute 22.10 %, C12 C17 constitute 27.90 %, C18-C24 constitute 20.13 %, balance heavy oil fractions (C25 to C 28). The analysis revealed the presence of alcohols in plastic oil. Since compounds with long chain oxygenated moieties and having hydroxyl group own appreciably more viscosity23, the presence of long chain fatty alcohols (1-Tricosanol, 1-Pentacosanol, 1-Decanol ) in plastic oil might be responsible for the increased kinematic viscosity than petro-diesel, which was also evidenced in physical property analysis. 3.1.

Effect of heating rate and residence time in pyrolysis Pyrolytic yield of HDPE plastic waste constituted of oil, wax, gas and residue. The effect of

heating rate on reaction time and yields obtained during the end of pyrolysis reactions at four different heating rates are shown in Figure 9. At a lower heating rate of 5 °C/min, condensate resulted in less


Energy & Fuels

Page 14 of 50

14 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

viscous liquid yield. At this heating rate, during early reactions, the initiation reaction might have prolonged for longer duration due to long residence time. During initiation reactions, C–C bond fission may occur to form radicals, with the favoured C–C break happening between the most highly substituted carbons.24 As the reaction continues, the liquid in the reactor might have allowed the catalyst to crack them further into flammable gaseous output. Due to presence of catalyst, at high residence time, further reduction in the molecular weight of the major chains might have occurred through successive reactions by Bronsted and Lewis acid sites25 in the catalyst. At the heating rate of 10 °C/min, primary catalytic cracking was achieved followed by condensable vapour generation, which resulted in high liquid yield. The reduced residence time might have prevented further production of lower molecular weight fractions. At a still higher heating rate (15 °C/min), the early production of high molecular weight fractions were resulted into vapours and gases, without full cracking, due to low residence time. The high molecular weight volatile vapours condensed in the condenser as wax and non-condensable gases escaped into atmosphere. This has caused low liquid yield and remarkable increase in wax yield. At the heating rate of 20 °C/min, more light weight fractions might have generated and resulted in high gaseous yield. This might be due to β-scission reactions occurring on the polymer chain end ahead of the radical transfer, since the rate of β-scission happen quicker at faster heating rates.26, 27 3.2. Variation of performance characteristics An increase of 7.16 % in brake specific fuel consumption was observed for plastic oil at rated load when comparing with petro-diesel (shown in Figure 10). This is due to lower heating value of plastic oil which demands more fuel to maintain the power output at peak load. The lower heating value of plastic oil is attributed by the presence alkanes in lower proportions when compared with petro-diesel. In addition, this could also be due to more fuel burning in premixed combustion phase because of high cetane index of plastic oil.


Page 15 of 50

Energy & Fuels

15 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

Brake thermal efficiency (BTE) is a measure of the combustion ability of an energy transformer for any fuel under study and reveals a comparative way of evaluation on the efficient conversion of the chemical energy in fuel into mechanical output. In case of plastic oil, an increase of 4.53 % in brake thermal efficiency was observed as against petro-diesel (shown in Figure 10) at rated load. This might be due to the presence of oxygenated functional groups in plastic oil (alcohols) and lower exhaust gas temperature (EGT) with consequent reduction of heat losses. At high loads more alcohols release more oxygen to aid combustion. In addition decreased ignition delay of plastic oil could cause easier exploitation of energy conversion than petro-diesel. The molecular structural dependency for the ease of exploitation of energy from the fuel is another factor which is discussed more in the sub section describing combustion characteristics. 3.3.

Variation of emission characteristics In this work, the engine emission namely, levels of NOx, CO, UHC and CO2 in exhaust gases are

presented on brake specific basis (g/kWh) and the smoke intensity is presented in terms of smoke opacity percentage. The results of brake specific CO (BSCO) and BSHC of petro-diesel and plastic oil are shown in Figure 11 A. BSHC emission in exhaust gases at peak load of plastic oil and petro-diesel were 0.156 and 0.14 g/kWh, respectively. The BSCO emission of plastic oil and petro-diesel were 4.8 and 4.3 g/kWh, respectively at rated load. A complete combustion is attributed by very low UHC levels in emission. This increase in BSHC (11.4 %) and BSCO (11.6 % ) values for the plastic oil were found due to the marginal higher value of the kinematic viscosity of plastic oil relative to petro-diesel which might have lead to poor atomization, vaporization of the fuel and incomplete fuel combustion. It is also evident from the results that a reduced trend prevailed in increase of UHC with increase in load in case of plastic oil. Obviously, at high loads the higher mass fraction of fuel will be involving in combustion. Hence, proportionately more oxygen might have aided combustion due to polar nature of alcohols28


Energy & Fuels

Page 16 of 50

16 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

present in plastic oil. Another contributing factor is the reduced heat release rate (HRR) of plastic oil relative to petro-diesel. Owing to the increased viscosity of plastic oil, minor changes in injection timing and injection pressure would be necessary to reduce the UHC and CO emissions which may be the scope of future work. At rated load of 4.4 kW, a decrease of 18.5 % in smoke opacity (Figure 11 B) was observed when using plastic oil as fuel relative to that of petro-diesel. The decrease in smoke opacity of plastic oil could possibly be due to the absence of aromatic content, presence of oxygenated moieties (alcohols) and formation of premixed combustion mixture before initiation of combustion. Though a consistent reduction in EGT and BSNOx were observed (Figure11 C) with plastic oil throughout the loads, a trend of increased reduction was noticed from mid load to peak load. At rated load, reduction of 20.09 % in EGT and 15 % in NOx emission were observed. The plastic oil has high cetane number that resulted into lower ignition delay. With increase in load and consequent increase in air-fuel mixture, more amounts of alcohols will be involving in combustion. Since alcohols are having high latent heat of vaporization, at peak load, this property might have predominated over the effect due to cetane value in combustion and resulted into combustion quenching.29 This phenomenon might possibly be responsible for increased reduction of NOx and EGT from mid load to peak load in the case of plastic oil. The increased oxygen content of the alcohols can improve the burning efficiency of the fuel blend, and reduce NOx emissions.30 3.4.

Variation of combustion characteristics The Figure12 represents the variation of heat release rate and cylinder peak pressure at peak load

with respect to crank angle for petro-diesel and plastic oil. It was noticed that the maximum heat release rate was 41.58 and 34.20 J/ °CA, for petro-diesel and plastic oil respectively at the rated load of 4.4 kW and rated rpm of 1500. The plastic oil was having higher cetane index and lower heating value than


Page 17 of 50

Energy & Fuels

17 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

petro-diesel. The presence of aromatics, having low cetane index, in petro-diesel is a contributing factor for reduction of cetane number. Alcohols are having more cetane index relative to aromatics. The relationship of hydrocarbon structural type and cetane number is of the order of: n-alkanes > alkens > cycloalkanes > hydroaromatics > n-alkyl aromatics; among alkanes, cetane number increases with increasing chain length.31 The reduction of heat release rate when using plastic oil was due to the reduction of ignition delay when compared with petro-diesel. Adding to that, moderate proportions of heavy carbon (C25 to C28) constituents present in plastic oil, which might demand high heat of combustion, is responsible for low heat release rate. The reduced heating value of plastic oil is due to presence of alkenes and alcohols whereas petro-diesel contains major proportions of alkanes. Hence this study explains that, reduction in heating value of plastic oil than petro-diesel, decreased ignition delay and presence of moderate proportions of heavy hydro carbons are contributing factors for decreased heat release rate. The ignition delay is considered as initial stage of combustion. The ignition delay is divided into two parts; the physical delay that includes the time duration for fuel atomization, vaporization and mixing of fuel with the air and the chemical delay which is the duration concerned with the preflame reactions and the acceleration until the local inflammation commences. Since the oxidation reaction in combustion is the process of branching-chain and free radical reactions, the molecular structure influences the chain process by determining the amount and availability of internal energy required for bond fission and relative attack at the C–H bonds with less effort.32 Obviously, this reaction kinetics is concerned with chemical ignition delay. The same authors reported further that, to improve the quality of combustion, adding a straight side chain to benzene ring lowers knock rating. Since the increased knocking is attributed by low cetane number of aromatics and consequential increase in chemical ignition delay, the petro-diesel fuel containing aromatics have more chemical ignition delay than plastic


Energy & Fuels

Page 18 of 50

18 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

oil. On the other hand, only a marginally higher viscosity was evidenced in plastic oil than petro-diesel. This is due to presence of polar compounds in plastic oil which inhibits minor increase in the physical ignition delay. Hence the possible reason for the overall increase in ignition delay of petro-diesel could be due to the presence of aromatics. Hence in case of plastic oil, decrease in experimentally observed ignition delay might possibly be due to remarkable decrease in the chemical part of ignition delay which is correlating with the results of chemical property and GC-MS analyses for its higher cetane number and nil aromatic content respectively. Ignition delay at different engine loads, for plastic oil and petro-diesel, are shown in Figure 13. When using petro-diesel as fuel, there is a gradual and consistent reduction ignition delay. A reduction in ignition delay from mid load to peak load was 21.5% and 30.7% for plastic oil and petro-diesel respectively. This trend of lesser reduction while using plastic oil might possibly be due to the unique characteristic of constituents present in it namely, high latent heat of vaporisation of alcohols. The lesser reduction of ignition delay with plastic oil at higher loads might be due to the effect of higher latent heat of vaporisation owing to the presence alcohols and more reduction at low loads might be due to high cetane index property of constituents other than alcohols present in plastic oil. This is reasonable because, lean air fuel mixture at low loads contain less polar compounds to combust where cetane index property predominates. Whereas at high loads, because of rich air fuel mixture to maintain same power output, demand of plastic oil might be more. Thereby more amounts of alcohols might have been exposed to combust which might have demanded more heat owing to high latent heat of vaporisation. This will cause combustion quenching and reduction in the in-cylinder temperature33, which in turn result in lower reduction in the cetane index as the load approaches peak value. The maximum cylinder pressure for the CI engine with petro-diesel and plastic oil as fuels were observed as 7.67 and 6.185 MPa, respectively at full load. The variation of peak cylinder pressure with


Page 19 of 50

Energy & Fuels

19 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

bmep for plastic oil and petro-diesel is shown in Figure 14. For a shorter ignition delay, fuel vaporization is instantaneous, little fuel is accumulated and major oxidation chemistry consists of degenerative chain branching reactions.34 For long ignition delay, fuel accumulation is severe, fuel rich mixture exists and combustion chemistry consists of chain branching explosions.34 Hence the petrodiesel with low cetane number and consequent longer ignition delay has possible reasons for the observed higher peak pressure. The drop in peak cylinder pressure of plastic oil might be due to its lower ignition delay, marginally increased kinematic viscosity and reduction in heat release rate. Though with the marginally increased in kinematic viscosity, the amount of fuel involved in the combustion and consequent energy density should increase, no substantial increase in the peak pressure had been noticed because of lower heating value of the plastic oil, poor atomization, low depth of penetration, reduced cone angle of spray, its high latent heat of vaporization at peak loads and higher cetane index. This trend is also agreeable with the other combustion characteristics discussed earlier. 4.

Conclusion From the above investigations and experimental results, the following conclusions are drawn. 1. Catalytic pyrolysis experiments at different heating rates with similar pyrolysis environment revealed that the optimum liquid yield was obtained at the heating rate of 10 °C/min. It is also found that, residence time decreased with rise in heating rate and might have brought changes in reaction kinetics. High gaseous yield had resulted at higher heating rate because β-scission reactions might have occurred ahead of the radical transfer. 2. The TG analysis and pyrolysis experiments revealed that simple method of chemical activation of bentonite clay had introduced the catalytic qualities.


Energy & Fuels

Page 20 of 50

20 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

3. The results of FTIR analysis revealed the presence of fuel range functional groups like alkyl, alkenyl, and hydroxyl. GC-MS studies of plastic oil revealed the presence of fuel range hydrocarbon compounds belonging to alkanes, alkenes, cycloalkanes and alcohols. 4. An increase of 4.53% in BTE at peak load, with plastic oil relative to petro-diesel, was due to the aid of oxygen content in alcohol for combustion. Lower EGT might have also resulted into lower heat losses. An increase of 7.16% of SFC was observed with plastic oil as a fuel in CI engine relative to petro-diesel due to inferior heating value of plastic oil, presence lower proportions of alkanes and more fuel in pre mixed combustion phase which might have demanded more fuel to maintain the cylinder pressure at peak load.

5. Marginally higher kinematic viscosity of plastic oil was responsible for the marginal increase in values of UHC and CO emissions. Further, the reduction in rate of rise of UHC and CO values with increase in load was due to high injection rates which might have exposed more polar compounds (Hydroxyl groups) with oxygen in plastic oil for combustion at high loads. The lesser heating value of plastic oil than petro-diesel, high cetane index and presence of moderate proportions of heavy hydro carbons are the contributing factors for the decreased heat release rate, NOx levels and EGT. Further, combustion of alcohols might have caused combustion quenching and reduced the EGT. 6. Since petro-diesel was having lower cetane number than plastic oil, 25.9 % increase in ignition delay was observed with petro-diesel at peak load. This might possibly be due to the molecular structural influence i.e. ring type structure of alcohols prolong the ignition by accumulated chainbranching explosions during combustion. This reason might be responsible for observed rise in peak pressure than plastic oil. The decrease in experimentally observed ignition delay for plastic


Page 21 of 50

Energy & Fuels

21 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

oil might possibly be due to remarkable decrease in the chemical part of ignition delay which is correlating with the results of chemical property and GC-MS analyses for its higher cetane number and nil aromatic content respectively. Further, as against the normal occurrence, (i.e. as the temperature increases with increase in load, ignition delay decreases more than that have occurred during low loads) a lesser reduction in ignition delay after mid loads was observed with plastic oil. This might be due to increase in chemical part of ignition delay consequent to the combustion of more polar compounds requiring high latent heat of vaporization. Nomenclature HDPE - high density polyethylene. DICI - direct injection compression ignition. TGA - thermo gravimetric analyses RIC – resin identification code SEM-EDS - scanning electron microscopy - energy dispersive X-ray spectroscopy DLS - dynamic light scattering LPG- liquefied petroleum gas FTIR- fourier transform infrared GC-MS- gas chromatography - mass spectrometry ASTM - american society for testing and materials UHC- unburned hydrocarbons


Energy & Fuels

Page 22 of 50

22 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

EGT - exhaust gas temperature RB- raw bentonite AB - activated bentonite DSC- differential scanning colorimetry DT - differential thermogravimetry BTE- brake thermal efficiency bmep – brake mean effective pressure. cps- counts per second. bTDC -before top dead centre. % T- percentage transmittance. BSHC - brake specific hydro carbon. BSFC - brake specific fuel consumption. Acknowledgements The authors wish to thank Dr. R. Karvembu, Department of Chemistry, National Institute of Technology, Tiruchirappalli, in sharing his knowledge and National Institute of Technology, Tiruchirappalli for the grant of necessary funds towards the pyrolysis experimental setup. References 1. Lin, Y.-H.; Yang M.-H., Chemical catalyzed recycling of waste polymers: Catalytic conversion of polypropylene into fuels and chemicals over spent FCC catalyst in a fluidized-bed reactor.


Page 23 of 50

Energy & Fuels

23 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

Polymer Degradation and Stability 2007, vol. 92, no. 5, pp 813-821, http://dx.doi.org/10.1016/j. polymdegradstab.2007.01.028. 2. Kyong-Hwan, L.; Geug-Tae, K.; Jeong-Gil, C., Effect of heating rate on pyrolysis of low-grade pyrolytic oil. Korean Journal of Chemical Engineering 2011, Volume 28, Issue 6, pp 1468-1473, http://dx.doi.org/10.1007/s11814-011-0065-x. 3. Levine, S.E.; Broadbelt, L.J., Detailed mechanistic modeling of highdensity polyethylene pyrolysis: Low molecular weight product evolution. Polymer Degradation and Stability 2009, 94(5): p. 810-822, http://dx.doi.org/10.1016/j.polymdegradstab.2009.01.031. 4. Scheirs, J.; Kaminsky, W., Feed stock recycling and pyrolysis of waste plastics: Converting waste plastics into diesel and other fuels. John Wiley & Sons, Ltd.: 2006, ISBN: 0-470-02152-7. 5. Su, S. L.; Howard, A. C., A review on waste to energy processes using microwave pyrolysis. Energies 2012, 5, 4209-4232, http://dx.doi.org/10.3390/en5104209. 6. Lam, S.S.; Russell, A.D.; Chase H.A., Microwave pyrolysis, a novel process for recycling waste automotive engine oil. Energy 2010, 35: 2985-2991, http://dx.doi.org/10.1016/j.energy.2010.03.033. 7. Punčochář, M.; Rujb B.; Chatterjeeb, P. K., Development of process for disposal of plastic waste using plasma pyrolysis technology and option for energy recovery. Procedia Engineering 2012, 42, 420-430, http://dx.doi.org/10.1016/j.proeng.2012.07.433 8. Geol Na, J.; Jeong, B-H.; Chung, S.H.; Soo Kim, S., Pyrolysis of low-density polyethylene using synthetic catalysts produced from fly ash. J Mater Cycles Waste Manag. 2006, 8:126-132, http://dx.doi.org/ 10.1007/s10163-006-0156-7.


Energy & Fuels

Page 24 of 50

24 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

9. Flessner, U.; Jones, D.J.; Rozière, J.; Zajac, J.; Storaro, L.; Lenarda, M. P.; Jiménez-López, A.; Rodr´ıguez-Castellón, E.; Trombetta, M.; Busca, G., A study of the surface acidity of acid-treated montmorillonite clay catalysts. Journal of Molecular Catalysis A: Chemica. 2001, 168, 247-256 10. Mochamad Syamsiro,; Harwin Saptoadi,; Tinton Norsujianto,; Putri Noviasri,; Shuo Cheng,; Zainal Alimuddin, ; Kunio Yoshikawa, Fuel Oil Production from Municipal Plastic Wastes in Sequential Pyrolysis and Catalytic Reforming Reactors. Energy Procedia 2014, 47, 180-188, http://dx. doi.org/ 10.1016/j.egypro.2014.01.212 11. Omar Gutiérrez,; Humberto Palza, Effect of carbon nanotubes on thermal pyrolysis of high density polyethylene and polypropylene. Polymer Degradation and Stability 2015, Volume 120, Pages 122-134, http://dx. doi.org/ 10.1016/j.polymdegradstab.2015.06.014 12. Narayanan, K. S.; Anand, R. B., Experimental investigation on optimization of parameters of thermo catalytic cracking process for H.D.P.E. & P.P. mixed plastic waste with synthesized Alumina-Silica catalysts. Applied Mechanics and Materials 2014, Vols. 592-594, pp 307-311, http://dx.doi.org/ 10.4028/www.scientific.net 13. Sadhik Basha, J.; Anand, R. B., Performance, emission and combustion characteristics of a diesel engine using carbon nanotubes blended jatropha methyl ester emulsions. Alexandria Engineering Journal 2014, Volume 53, Issue 2, Pages 259-273, http://dx.doi.org/10.1016/j.aej.2014.04.001. 14. Holman, J.P., Experimental methods for engineers; Seventh edition, McGraw-Hill Company: New York, 2001, pp 48-62. 15. Huang, J.; Jiang, Y.; Marthala, V.R.R.; Thomas, B.; Romanova, E.; Hunger, M.; Characterization and acidic properties of aluminum-exchanged zeolites X and Y. J. Phys. Chem. C 2008, 112 (10), 3811-3818, http://dx.doi.org/10.1021/jp7103616.


Page 25 of 50

Energy & Fuels

25 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

16. Angaji, M. T.; Zinali, A. Z.; Qazvini, N. T., Study of physical chemical morphological alterations of smectite clay upon activation and fictionalization via the acid treatment. World Journal of Nano Science and Engineering 2013, 3, 161-168, http://dx.doi.org/10.4236/wjnse.2013.34019. 17. Seka Simplice Kouassi; Jonas Andji; Jean-Pierre Bonnet; Sylvie Rossignol, Dissolution of waste glasses in high alkaline solutions. Ceramics-Silikáty 2010, 54 (3) 235-240. 18. Kamal, K.T.; Tagelsir, M.S.; Musa, A.M., Performance of Sudanese activated bentonite in bleaching cottonseed oil. Journal of Bangladesh Chemical Society 2011, Vol. 24(2), 191-201, http://dx.doi.org/10.3329/jbcs.v24i2.9708. 19. Sachin Kumar; Singh, R. K., Pyrolysis kinetics of waste high-density polyethylene using thermogravimetric analysis. Int.J. ChemTech Res. 2014, 6(1), pp 131-137. 20. Coats, J., Interpretation of infrared spectra, a practical approach. Encyclopedia of Analytical Chemistry, R.A. Meyers (Ed.), John Wiley & Sons Ltd., Chichester : 2000, pp. 10815-10837. 21. Sarker, M.; Rashid, M., M.; Molla, M., Abundant high-density polyethylene (HDPE 2) turns into fuel by using of HZSM-5 catalyst. Journal of Fundamentals of Renewable Energy and Applications 2011, Vol. 1, Article ID R110201, 12 pages, http://dx.doi.org/10.4303/jfrea/R110201 22. Kulkarny, B.M.; Pujar, B.G.; Shanmukhappa, S., Investigation of acid oil as a source of biodiesel. Indian Journal of Chemical Technology 2008, Vol, 15, pp 467-471. 23. Gerhard K.; Kevin R. Steidley, Kinematic viscosity of biodiesel fuel components and related compounds. Influence of compound structure and comparison to petro-diesel fuel components. Fuel 2005, 84, 1059-1065, http://dx.doi.org/10.1016/j.fuel.2005.01.016.


Energy & Fuels

Page 26 of 50

26 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

24. Magdy, M.; Samia, A. H.; Mamdouh S. E.; Sahar M. A.; Nahla A. M.; Mohamed S.A. D.; Dalia E. A., Wax co-cracking synergism of high density polyethylene to alternative fuels. Egyptian Journal of Petroleum 2015, 24, 353–361, http://dx.doi.org/10.1016/j.ejpe.2015.07.004 25. Neha P.; Pallav, S.; Shruti, A.; Piyush S., Alternate strategies for conversion of waste plastic to fuels. ISRN Renewable Energy 2013, Volume 2013, Article ID 902053, 7 pages. 26. Rangarajan, P.; Bhattacharyya, D.; Grulke, E., HDPE liquefaction: Random Chain Scission Model. J. of Applied Polymer Science 1998, 70, (6), 1239-1251. 27. Achyut, K. Panda; Singh, R.K.; Mishra, D.K., Thermolysis of waste plastics to liquid fuel, A suitable method for plastic waste management and manufacture of value added products-A world prospective, Renewable and Sustainable Energy Reviews 2010, 14, 233-248, http://dx.doi.org/10.1016/j.rser.2009.07.005. 28. Li, D.; Zhen, H.; Xingcai, .L; Wu-gao, Z.; Jian-guang, Y., Physico-chemical properties of ethanoldiesel blend fuel and its effect on performance and emissions of diesel engines. Renewable Energy 2005, 30, 967–976, http://dx.doi.org/10.1016/j.renene.2004.07.010 29. Mani, M.; Subash, C.; Nagarajan, G., Performance, emission and combustion characteristics of a DI diesel engine using waste plastic oil. Applied Thermal Engineering 2009, Volume 29, Issue 13, Pages 2738–2744, http://dx.doi.org/10.1016/j.applthermaleng.2009.01.007 30. Hajba, L.; Eller, Z.; Nagy, E.; Hancsok, J., Properties of diesel-alcohol blends. Hungarian Journal of Industrial Chemistry 2011, Veszprem, Vol. 39, (3), pp. 349-352.


Page 27 of 50

Energy & Fuels

27 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

31. Chunsham, S.; Chang S.; Hsu, Isao M., Chemistry of Diesel Fuels. Tailor & Francis: 2000, ISBN, 1-56032-845-2, pages 316. 32. Wendell, P. Hawthorne; Eric, J.Y. Scott, Literature of The Combustion of Petroleum, Structural factors determining knocking characteristics of pure hydrocarbons. American Chemical Society: 1958, Vol. 20, Chapter 14, pp 187-201, http://dx.doi.org/ 10.1021/ba-1958-0020.ch014. 33. Sukjit, E.; Herrerosb, J.M.; Dearn, K.D.; García-Contreras, R.; Tsolakis A., The effect of the addition of individual methyl esters on the combustion and emissions of ethanol and butanol diesel blends. Energy 2012, Volume 42, Issue 1, Pages 364-374, http://dx.doi.org/10.1016/j.energy.2012.03.041. 34. Eugene L. Keating, Applied Combustion. CRC Press: 2007, pp 457-458.


Energy & Fuels

Page 28 of 50

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

Figure Captions: Figure 1. Catalyst activation setup. Figure 2. SEM image of activated bentonite. Figure 3. FTIR spectra of plastic oil. Figure 4. GC-MS spectra of plastic oil. Figure 5. Schematic layout of engine experimental setup. Figure 6. DSC endotherms of plastic waste with and without catalyst at a heating rate of 10 °C/min., denoting phase transition, degradation temperatures and heat flow. Figure 7. TG-DSC endotherms of HDPE plastic waste without catalyst at a heating rate of 10 °C/min., denoting maximum weight loss temperature, degradation temperatures and heat flow. Figure 8. TG endotherms of HDPE plastic waste. Figure 9. Effect of heating rate on residence time, plastic oil yield, residue, wax and gas. Figure10. Variation of engine performance parameters (BTE and BSFC). Figure11. Variation of engine emission characteristics (A= BSCO and BSHC, B= BSCO2 and Smoke, C= EGT and BSNOx). Figure 12. Variation of combustion parameters of engine at the rated load. Figure 13. Variation of engine ignition delay with bmep. Figure 14. Variation of cylinder peak pressure with bmep.


Page 29 of 50

Energy & Fuels

29 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

Table captions: Table 1. Physical and rheological properties of HDPE plastic waste. Table 2. Elemental analysis of raw materials and their comparison with petro-diesel.. Table 3. Results of physical, thermal and chemical properties of plastic oil and petro-diesel. Table 4. Results from FTIR analysis of plastic oil indicating the functional groups. Table 5. Summary of results from GC-MS analyses of plastic oil and their comparison with petrodiesel. Table 6. Technical specifications of engine experimental setup. Table 7. Estimated and calculated values of uncertainty.


Energy & Fuels

30 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

1 = Stirrer motor 2 = Resistant temperature detector 3 = Temperature controller 4 = Heater 5 = catalyst solution

Figure 1. Catalyst activation setup.


Page 30 of 50

Page 31 of 50

Energy & Fuels

31 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 2. SEM image of activated bentonite.


Energy & Fuels

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

Figure 3. FTIR spectra of plastic oil.


Page 32 of 50

Page 33 of 50

Energy & Fuels

33 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 4. GC-MS spectra of plastic oil.


Energy & Fuels

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

1. Data acquisition system, 2. Exhaust gas analyzer, 3. Smoke opacity meter, 4. Load, 5. Pressure pickup, 6. Exhaust gas temperature output, 7. Crank angle pickup, 8. Exhaust pipe, 9. Fuel supply.

Figure 5. Schematic layout of engine experimental setup (Sadhik Basha et.al)13 lAl.aaaaaaaaa


Page 34 of 50

Page 35 of 50

Energy & Fuels

35 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

----- Plastic waste with catalyst _____

Plastic waste without catalyst

Figure 6. DSC endotherms of plastic waste with and without catalyst at a heating rate of 10 °C/min., denoting phase transition, degradation temperatures and heat flow.


Energy & Fuels

36 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 7. TG-DSC endotherms of HDPE plastic waste with catalyst at a heating rate of 10 °C/min., denoting maximum weight loss temperature, degradation temperatures and heat flow.


Page 36 of 50

Page 37 of 50

Energy & Fuels

37 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 8. TG endotherms of HDPE plastic waste ( Sachin Kumar)19


Energy & Fuels

Page 38 of 50

38

Residence Time (min)

Reisdue, %

Plastic Oil Yield, %

Wax, % Gas, %

5.2 % 21.9 %

260 min

100

8.3 %

11.4 %

250

25.6 %

4.3 %

80

23.7 %

12.2 % 2.1 %

200

32.8 %

8.9 %

60

79.1 %

150

65.9 % 0.9 %

40

95 min

100

70 min

57 %

40.7 % 55 min

50 0

20

Plastic Oil Yield, Residue, Wax, Gas (%)

300

Residence Time (min)

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

0 5

10

15

20

Heating Rate ( oC/min )

Figure 9. Effect of heating rate on residence time, plastic oil yield, residue, wax and gas.


Page 39 of 50

Energy & Fuels

39

40

BTE (Petro-diesel)

BSFC (Petro-diesel)

BTE (Plastic Oil)

BSFC (Plastic Oil)

1250

30

750

20

500

10

0 0.00

BSFC (g/kW-h)

1000

BTE (%)

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

250

0 0.08

0.15

0.23

0.30

0.38

0.45

0.53

bmep (MPa)

Figure 10. Variation of engine performance parameters (BTE and BSFC).


Energy & Fuels

Page 40 of 50

40

BSCO (Plastic oil)

A 0.45

BSHC (Plastic oil)

15

BSHC (Petrodiesel)

0.30 10

0.15

5

0 Smoke (Plastic oil)

BSCO2 (Petro-diesel)

Smoke (Petro-diesel)

B

BSCO2 (g/kW-h)

800

20

600

15

400

10

200

5

0

0

500

o

25

EGT (Petro-diesel)

BSNOx (Petro-diesel)

EGT (Plastic Oil)

BSNOx (Plastic Oil)

C

20

400

16

300

12

200

8

100

4

0

0 0.00

0.08 0.15

0.23 0.30

0.38 0.45

Smoke (%)

1000

0.00 BSCO2 (Plastic oil)

BSNOx (g/kW-h)

BSCO (g/kW-h)

BSCO (Petro-diesel)

BSHC (g/kW-h)

20

EGT ( C)

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

0.53

bmep (MPa)

Figure 11. Variation of engine emission characteristics (A=BSCO and BSHC, B= BSCO2 and smoke, C= EGT and BSNOx). ACS Paragon Plus Environment

Page 41 of 50

Energy & Fuels

41

Cylinder Peak Pressure x 10 (MPa)

100 Petro-diesel Plastic oil

80

60

40

20

0 Heat Release Rate (J/deg. CA)

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

Petro-diesel Plastic oil

50 40 30 20 10 0 -10 300

320

340

360

380

400

420

440

Crank angle (degree)

Figure 12. Variation of combustion parameters of engine at the rated load.


Energy & Fuels

Page 42 of 50

42

10

Petro-diesel

Plastic Oil

8

6

o

Ignition Delay ( of crank angle)

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

4

2

0 0.00

0.08 0.15

0.23 0.30

0.38 0.45

0.53

bmep (MPa) Figure 13. Variation of engine ignition delay with bmep.


Page 43 of 50

Energy & Fuels

Cylinder Peak Pressure (MPa)

43 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

Plastic Oil

Petro-diesel

8

6

4

2

0 0.00

0.08 0.15

0.23 0.30

0.38 0.45

bmep (MPa) Figure 14. Variation of cylinder peak pressure with bmep.


0.53

Energy & Fuels

Page 44 of 50

44 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

Table 1. Physical and rheological properties of HDPE plastic waste. Sl. No.

Property

Test standard

Density

0.948 g/cm3

ASTM D 1505-10

Melt flow index

7 g/10 min

ASTM D1238-13

Melting point

138.12 °C

From DSC analysis


Page 45 of 50

Energy & Fuels

45 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

Table 2. Elemental analysis of raw materials, their comparison with petro-diesel and plastic oil.

HDPE plastic waste

Petro-Diesela

HDPE Plastic oil

Composition Test results (weight %) Values (weight %) Test results (weight %) Carbon (C) 85.61 86.4 84.56 Hydrogen (H) 14.08 13.6 14.01 Nitrogen (N) Nil Nil Nil Sulphur (S) 0.00 Nil Nil Oxygen (O)/others 0.31 Nil 0.22 Elemental analysis of raw bentonite before and after activation. Test results in Source of raw bentonite Composition normalized weight % Before After activation activation M/S Micamin Exports, India. O 56.51 52.82 Si 16.78 12.33 Al 3.61 1.44 Ca 11.31 14.81 Mg 6.33 0.95 Fe 3.99 1.61 K 1.47 Nil S Nil 1.25 C Nil 5.79 a ( values reported in Kulkarny et al.22)


Energy & Fuels

Page 46 of 50

46 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

Table 3. Results of physical, thermal and chemical properties of plastic oil and their comparison with standard values of petro-diesel. Fuel property

Unit

Result

Test method

Density @15 °C Kinematic viscosity @40 °C Flash point Sulphur content Gross Heating value Acidity

g/cc cSt

0.860 4.60

ASTM D 1298 ASTM D 445

Petro-diesel - (Gr. No. 2D S500 as per ASTM D 975-07) 0.84-0.86 1.9- 4.1

°C % MJ/kg mg of KOH/g °C -

49 0.34 41.35 0.49

ASTM D 92 ASTM D 129 ASTM D 240 ASTM D 974

52 (minimum) 0.5 42- 45b --

< -15 56

ASTM D 97 ASTM D 976

-16 (minimum) 40(minimum)

Pour point Calculated cetane index b (Sachin Kumar19)


Page 47 of 50

Energy & Fuels

47 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

Table 4. Results from FTIR analysis of plastic oil indicating the functional groups. Functional Group

Assignment c

−CH3 - Branched Alkane Methyl C−H asym. stretch CH2 - Branched Alkane Methylene C−H asym. stretch CH2 - Branched Alkane Methylene C−H sym. stretch C=C - Alkene Alkenyl C=C stretch ( CH2) -Alkane Methylene C−H bend −CH3 - Alkane Methyl C−H sym. stretch C−O - Alcohol Tertiary alcohol, C−O stretch =C−H - Alkene trans- C−H out-of-plane bend C−H - Alkene Vinylidene C−H out-of-plane bend ( CH2) -Alkane Methylene − (CH2)n− rocking c Assignment reference for interpretation of spectra (Coats20)


Wave number (cm-1) 2955.79 2922.96 2854.17 1650.10 1457.17 1377.16 1151.51 966.03 887.40 721.95

Energy & Fuels

Page 48 of 50

48 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

Table 5. Summary of results from GC-MS analysis of plastic oil and their comparison with petro-diesel. Sl.No. Compound belonging to 1 2 3 4 5 d

Alkane Alkenes/Olefins Aromatics Cycloalkanes / Naphthene Alcohol

Composition % Plastic oild Diesele 22.43 67.4 41.47 3.4 20.1 9.06 9.1 26.16

-

Determined by GC-MS characterization, e( Kulkarny et al.22)


Page 49 of 50

Energy & Fuels

49 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

Table 6. Technical specifications of engine experimental setup Engine details Make/Model Type Bore & Stroke Length of connecting rod Compression ratio Swept volume Combustion chamber Nozzle Spray cone angle Rated output & speed Injection timing Injection pressure Data Acquisition system Type Specifications

Signal conditioning Pressure Transducer Make Model No. Measuring Range Sensitivity

Kirloskar/TAF1 Single cylinder, four stroke, naturally aspirated, air cooled, constant speed, direct injection. 87.5 × 110 mm 220 mm 17.5:1 661 cc Open hemispherical 3 holes, 0.25 mm diameter 110° 4.4 kW 26° bTDC 215 bar (21.5 MPa) Run Time, Windows XP 12 bit, 8 channel analog-digital conversion, 12 bit channel digital-analog conversion, 4 digital input, 4 digital output, USB compatible. Stand alone for each sensor KISTLER 6613CA 0-100 bar 25 mV/bar


Energy & Fuels

Page 50 of 50

50 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

Table 7. Estimated and calculated values of uncertainty. Sl. No

Quantity/Instrument

1

AVL Five gas analyzer

2 3 4 5 6 7 8 9

AVL Smoke opacity meter Exhaust gas temperature Speed measuring unit Alternator output (Brake load) In cylinder gas pressure Crank angle encoder Digital stop watch Brake thermal efficiency

Measuring range CO, 0 - 10 % Vol. UHC, 0 - 20000 ppm CO2, 0 - 20 % Vol. O2, 0 - 22 % Vol. NOX, 0 - 5000 ppm 0 - 100 % 0 - 1000 oC 0 - 5000 rpm 6 kW 0 - 100 bar 0 - 360 oCA +0.5 to - 0.5 sec -


Percentage uncertainty ± 0.3 ± 0.2 ± 0.2 ± 0.2 ± 0.2 ± 0.1 ± 0.1 ± 0.5 ± 0.5 ± 0.1 ± 0.2 ± 0.2 ± 1.24

Experimental Investigation on Thermocatalytic Pyrolysis of HDPE

Recommend Documents